Category: Buying Solar

How Long Do Solar Panels Last?

How Long Do Solar Panels Last?

Andru Rothenberg
ANDRU ROTHENBERG, Purchasing Agent at Wholesale Solar​

Investing in solar energy is a long-term commitment. The up-front cost can be hefty, but the investment pays for itself over time through tax incentives and monthly savings on your energy bill.

For people trying to calculate the value of their investment over time, one of the first questions we receive is: “how long do solar panels last?”

Panels are typically warrantied for 25 years, so you can expect them to last at least that long. But in reality, studies have shown panels continue to operate at reduced efficiency long after the warranty expires.

Let’s do a little math: solar panels suffer a 0.5% to 1% efficiency loss every year. At the end of a 25-year warranty, your panels should still produce energy at 75-87.5% of their rated output.

According to an NREL study [PDF], nearly 80% of solar panels last longer than their warranty.

Standard Solar Panel Warranties

The typical warranty for solar panels is 25 years. During this period, manufacturers guarantee that panels will operate at or near peak efficiency. Most panels are covered to produce at least 80% of their rated output over the life of the warranty.

For example, a 300 watt panel should produce at least 240 watts (80% of its rated output) at the end of a 25-year warranty.

Some companies offer 30 year warranties or promise 85% efficiency, but these are outliers. The standard is 25 years at 80% efficiency.

Solar panels also have a separate workmanship warranty, to cover any manufacturing defects, such as a faulty junction box or frame. Typically the workmanship warranty is 10 years, with some manufacturers offering a 20 year workmanship warranty.

So…How Long Do Solar Panels Last, Really?

So what happens after the 25 year mark is up? Panels that output at 80% efficiency still work, right?

There aren’t any tricks here – the answer is yes! If your panels still output energy, there’s no real reason to replace them.

Panels frequently produce energy long after their warranty expires. According to a 2012 study by the National Renewable Energy Laboratory [PDF], the average degradation rate for panels is between 0.5% to 0.8% per year.

What is degradation rate? 

Degradation rate is the rate at which solar panels lose efficiency over time. A panel with a degradation rate of 1% per year will be 10% less efficient after 10 years.

In fact, 78% of systems tested had a degradation rate of less than 1% per year. That means that after 25 years of use, about 4 out of 5 solar panels still operate at 75% efficiency or better.

At this point, it’s fair to estimate your solar panels will still produce energy in some capacity, long after the warranty is up. For a great example, check out this 30-year old panel featured in Green Building Advisor. When the owner pulled it off his roof and ran it through tests, it still performed better than the factory specifications.

Here’s What That Means For Your ROI

That’s good news if your main concern is making a positive return on investment (ROI) on your system.

Most online calculators that estimate solar savings base the calculation on a 25-year warranty period. Any extra mileage you get from your panels is an added bonus.

Is solar a smart investment? Use our Solar ROI Calculator to estimate your payback period how long it will take for tax incentives and energy bill savings to pay for the upfront cost of your system.

We can’t guarantee panels will outlive their warranty (that’s the point of a warranty, after all). But in reality, most panels keep producing at reduced capacity long after their lifespan should be up. This is because solar panels don’t have any moving parts, and therefore tend to be extremely reliable.

If your solar system is paid off and your panels keep producing, your ROI will stretch far beyond the estimate provided to you by any online calculators (including ours).

Want to give your panels the best chance to outlast their warranty? A little effort goes a long way to keeping your system running smoothly.

How to Extend the Life of Your System

Keep in mind solar panels are likely going to be the most resilient part of your solar system. You’ll still need to maintain or replace inverters and batteries to keep everything running.

Inverters have a shorter lifespan than your panels, and will need to be replaced regardless of what type of system you have. If you’re off-grid (or grid-tied with a battery backup), battery maintenance and replacement will add extra costs for you down the line.

The best way to protect your investment is to inspect the system thoroughly upon installation. Check your racking to make sure the panels and wiring are secure. The biggest threats to the life of your panels are physical damage or electrical failure due to subpar installation.

Replace Inverters After 10 Years

Most grid-tie inverters have a 10-year warranty, and many manufacturers give the option to upgrade to 20 to 25-year warranty coverage.

Warranty extensions for inverters are a smart investment. It’s safe to assume you’ll replace your inverter at least once before the warranty on your panels is up. If your inverter fails 15 years down the road, it will likely be replaced with a newer and better model.

Check with the inverter manufacturer about their extended warranty options and policies. Extended warranties are purchased directly from the manufacturer. SMA and SolarEdge currently both offer modestly priced inverter warranty extensions.

Off-grid inverters have shorter warranties. They range from 1-5 years, with extensions up to 10 years available for a few models.

When you purchase an extended warranty, look over the little details carefully. Some cover the cost of parts, but not the cost of labor.

This might not bother you if you plan on swapping out the inverter yourself. But you may pay out of pocket if you need a contractor to replace the inverter down the line.

Maintain and Replace Batteries

Battery maintenance and replacement is one of the main expenses associated with off-grid systems. Even lower-upkeep battery types, like lithium and sealed lead acid batteries, still need to be inspected a few times per year.

Most batteries come with a warranty of 3-10 years, depending on the brand. But if you don’t care for your batteries properly, they can fail within the first year of ownership.

For example, lead acid batteries need to be fully recharged after being used, and they will be permanently damaged if they sit for extended periods without being recharged.

Most high-quality off-grid deep cycle batteries will last between 5-15 years, depending on the battery type and how they are used and maintained. You can extend the life of your batteries by caring for them properly and by ensuring they’re installed correctly.

The best thing you can do is design your system properly from the start. Account for the proper amount of battery capacity, solar power, and inverter output up front to keep everything working properly.

Account For Efficiency Loss

Here’s the main takeaway: it’s highly unlikely that you will need to replace your solar panels before the warranty is up. Solar panels last a long time – longer than the other parts of the system.

However, the efficiency loss may mean your system no longer covers your energy needs. If your system output shrinks (or your energy usage grows), it’s possible to add capacity to your system, assuming the old and new parts are compatible. For more on that process, see our guide to expanding your solar energy system.

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How Many Solar Panels Do I Need?

How Many Solar Panels Do I Need?

IAN SHURTLEFF, Sales and Design Tech at Wholesale Solar​

One of the most common questions our design technicians get is: “How many solar panels do I need?”

The answer is pretty complex, and frankly, most people approach it from the wrong angle when they start to look into solar.

We’re often asked to quote a system to power a 3-bedroom home or a support a family of 4. In these situations, it’s impossible to provide an accurate estimate until we know more about the household’s energy needs.

In reality, the best place to start is to evaluate your current energy use based on past electric bills. Past usage data is the best baseline to figure out how many panels you will need.

Lifestyle, climate and panel efficiency all play a role in figuring out the size of your solar system. Here’s the process we use to make an accurate estimate.

How many panels for grid-tied systems?

In order to figure out just how many panels you need, you’ll want to gather up 6 months to a year’s worth of electric bills. If you live in an area with snowy winters or blistering hot summers, look at a larger sample of bills to understand when your usage spikes. Take peak periods into account as you estimate how many panels you’ll need to cover your energy usage.

Some companies provide a 12-month summary of how much electricity you use on every bill. Depending on your utilities provider, you may just need one bill to find an estimate for the year.

Got your paperwork in order? Great – you want to look for how many kilowatt hours (kWh) of electricity you use per year.

Wait, what’s a kilowatt hour?

A kilowatt hour (kWh) is a measurement of energy. If an appliance rated for 1 kilowatt (1000W) runs for an hour, then one kWh of energy has been used.

The energy company measures total energy usage in kilowatt hours. Your total usage in kilowatt hours determines how much you are billed each month.

Example 1: A fridge rated at 250 watts runs for 4 hours per day. 250W x 4 = 1000W, or 1 kW. This fridge uses 1 kWh of energy over the course of a day.

Example 2: An oven is rated at 2000 watts (2 kW). Cooking in this oven for half an hour would consume 1 kWh of power (2kw x 0.5 hours = 1kWh).

Find how many kWh of energy you use per year. That will give you a good jumping off point for estimating your energy needs – but you’re not there yet.

Divide that number by 365 to get your daily energy usage in kWh.

Once you have your daily energy usage, use this formula to estimate your total system size:

Daily Usage (kWh) ÷ Sun-Hours ÷ 0.9 inefficiency factor = Minimum Solar Array Output

Sun-hours refers to how much sun you get each day where you live. You can find that info on our US sun-hours map. More on this a bit later.

The inefficiency factor simply accounts for circumstances that would make your system run below its optimal output, like shade, extreme temperatures, voltage drop and equipment inefficiencies.

Take your daily usage and divide it by these two numbers to get an estimate of the overall output of your system.

For example:

According to the U.S. Energy Information Administration, the average American household used 10,766 kWh of electricity annually in 2016. That’s about 29.5 kWh per day.

Let’s say you live in Arizona, which gets 5.5 sun-hours per day.

29.5 kWh per day ÷ 5.5 sun-hours ÷ 0.9 = 5.9595 kW capacity system.

That would give you an approximate system size of 5.96 kW, or 5959W (remember, 1 kilowatt = 1000 watts).

From there, the last step is to divide by the energy rating of each individual panel. Solar panels are graded by how much power they use. The panels you would use in a residential setting typically range from 275 to 350 watts per panel.

Let’s say we want to use Astronergy 325W panels. Take your system size and divide by the panel wattage to figure out how many solar panels you need in your system:

5959W ÷ 325W = 18.33 panels

Round up the final number, since you can’t buy partial panels. In this scenario, we would need 19 panels rated at 325 watts apiece to cover our energy needs.

We can’t stress this enough: this calculation is a very rough estimate. It should only be used to ballpark system size and make early pricing estimates.

But don’t take this estimate as gospel – there are too many factors that can change the size of your system in practice.

Additional considerations for off-grid systems

Calculating power consumption needs for an off-grid system is a tad more complicated. People who live off-grid need to focus on daily power usage rather than monthly or annual consumption.

You’re not staring down a power bill each month – you’re independent and responsible for covering your own day-to-day power needs. The system needs to be able to produce enough (and store enough) to keep things running smoothly.

Without power bills as a starting point, it’s best to start by listing out your major appliances and estimating how much you use them on a daily basis. Input this list into our Load Evaluation Calculator.

If you’re not sure how much power an appliance uses, follow the appliance electrical consumption table as a guide. You can also check for the EnergyGuide sticker, or use a meter to measure energy consumption if possible.

This form will give an estimated daily usage.

Pay close attention to December and January when you estimate your energy needs. Those months tend to have the highest power usage and the lowest output by your system.

When you live off-grid, you will need a battery system that’s large enough to store enough power for the day and then use solar power to recharge them in a timely manner. It’s common to lean on a backup generator during the winter, when there won’t be enough sunlight to fully power your solar system.

Once you know how much power you use in kWh per day, a solar design technician can determine the minimum battery size needed with a formula that accounts for things like inefficiencies and temperature coefficients.

Here are the basic formulas we use to size off-grid systems:

Minimum Battery capacity (for lead acid batteries):

Daily usage (kWh) x 2 for a 50% discharge depth x 1.2 inefficiency factor = Minimum Battery Capacity

Minimum Solar Array Size

Daily usage (kWh) ÷ Sun-hours ÷ .9 inefficiency factor = Minimum Solar Array Output*

*Ensure solar array meets battery charge requirements, typically around 10 charging amps per 100ah battery capacity.

You may need a larger array or battery bank based on your location, ambient temperature, your usage patterns and other factors. Take a look at our Battery Bank Sizing Calculator to help figure out how many batteries you need to power your system.

Factoring in sun-hours based on your location

“Sun-hours” refers to how much solar energy hits a given area over a certain amount of time.

Your local climate determines how many peak sun-hours you get each day. This number can change drastically based on where you live. If you live in the United States, you can check out our Solar Insolation Map to get an estimate of how many sun-hours you receive in your area.

It’s important to keep in mind that the term “sun-hours” doesn’t just refer to the hours of daylight that your area receives. The peak hours occur when the sun is at its highest in the sky, which will change based on the season and how close you are to the equator. In the winter, the average sun-hours in your location could decrease by 25% to 50%.

So how do sun-hours affect the number of panels on your solar system? If you live in an area with less sun-hours, you’ll need more panels to capture what you need to cover 100% of your energy usage. However, if you live in an area that gets 5-6 sun-hours per day, you might be able to get by with a smaller system.

Quality vs. quantity: panel efficiency isn’t everything

Another aspect that affects the size of your system is the efficiency of the solar panels themselves. Most residential panels range from 275W to 350W. If you go with a 275 watt option, you’ll need several more panels to build your array.

When it comes to solar, efficiency isn’t always the most important factor to consider when you build your system. It really depends on what your specific goals are.

For example, if you look at your solar panels primarily as an investment and a quick ROI is your biggest goal, you might be better off with a lower output, lower cost panel.

“If a panel is 50% more efficient, but costs 100% more, you’re better off paying for [a larger system] of less efficient panels.”

-Brady Schimpf, technical marketing engineer at Ironridge

Brady Schimpf, technical marketing engineer at Ironridge, he had a few thoughts on this matter. He said one of the most common mistakes he sees people make is that they buy into ultra-efficient, high-quality, and technically advanced system, and it might not be worth it – especially if ROI is your biggest concern.

“While a lot of the proprietary systems like that have really good equipment, it is important to look at the cost per watt,” he explained. He urges consumers to consider this: “How much are you paying for the total wattage/production of the system?

“It doesn’t really matter how efficient a panel is if it costs a lot more. If a panel is 50% more efficient, but costs 100% more, you’re better off paying for [a larger system] of less efficient panels.”

But there are some circumstances where having a smaller yet more efficient solar system makes sense. For example, if your roof space is really limited, you might need a more efficient system to cover your energy needs within that given area.

Considering other variables when designing a solar system

We can’t stress this enough: this breakdown only serves as a very rough estimate and a starting point for planning your system.

It’s great to get you closer to a ballpark figure on the cost of panels. It will help as a benchmark when you measure your roof to see if you can fit a system up there.

But when you get deeper into planning your system, unexpected hurdles always come up and the system size tends to change.

What if you decide to go with 275W panels instead of 350W panels because the cost-per-watt is lower? What if shade covers your system, or your roof doesn’t directly face the sun? What if harsh weather causes your equipment to perform below its rated efficiency? What if you start using more energy than you did in the past?

Yup . . . you’ll need more panels.

Although this breakdown can give you an estimate of how many solar panels you’ll need in your array, at the end of the day it’s just an estimate. There are several other variables that can determine the size of your solar system, but this process is still important as it gives you an idea of what to look for before you seek out quotes on solar systems.

If you’re interested in going solar, the best thing you can do is speak with a solar design technician that can help you find the ideal system for your unique situation. Bring your estimate as a starting point. We’ll go over any potential problems and tweak the design to suit your location and lifestyle.

Expanding Your Off-Grid Solar System? Here’s What You Need to Know

Expanding Your Off-Grid Solar System? Here’s What You Need to Know

JEREMY CHAMPT, Senior Sales Tech at Wholesale Solar​

There’s nothing quite like the sense of independence that comes from living off-grid.

But with that sense of freedom comes the responsibility of providing for your own energy needs – and it can be frustrating if your solar system struggles to supply power for the things you do on a daily basis.

You might find that your energy needs have evolved over time. Or maybe the system wasn’t sized to accommodate surges of heavy usage, and you need a little extra juice to cover peak output periods.

Thankfully, most off-grid systems can be expanded with additional panels, inverters, and a bigger battery bank.

When does it make sense to expand?

Before we tell you how to expand your off-grid system, you should work out why you need to add on to your system in the first place.

There are a few situations where modular expansion makes sense:

  • Budget constraints. It’s fine to start with a small system, then expand in the future as your budget allows.
  • Increased energy consumption. Your energy usage can change if more people move on to the property, or you buy more stuff that needs to be powered.
  • Insufficient solar production. If your system wasn’t sized to account for high-usage periods, it might need a few tweaks.

Budget Constraints

An off-grid solar system is a big purchase. Not everyone has the cash on hand to buy a system that will cover 100% of their energy needs.

Fortunately, you can build your system in small installments rather than make one large purchase outright. It’s a great way to approach your off-grid installation  but it requires a bit of planning in advance.

Our designers always recommend building a system with future expansion in mind. Regardless of whether you choose a roof-mount or ground-mount racking system, make sure your setup leaves space to tack on extra panels.

You should also be aware that inverters and batteries have their own capacity limits. If you add more panels, you’ll likely pair them with new inverters and batteries to keep pace with the extra output.

Not sure what size system you need? Calculate an estimate here.

On the flip side, it’s also worth considering how much more expensive this piecemeal installation method can be the long run. You should be aware of the drawbacks of building a system step-by-step:

  1. Panel Consistency

If you go years between additions to the system, it could be challenging to find panels that are the same make and model as your existing system. Solar tech advances rapidly, and companies update their product lines to keep in line with the latest innovations.

Thankfully, this is not too big of an issue. Most panels have a standard voltage and size, so a new panel will likely be compatible with an old system. There will be cosmetic differences, but a mix-and-match system should function just fine.

In general, it’s fine to mix and match panels as long as they are within 1 volt. Electrical specs and sizes are standardized (60-cell and 72-cell panels are common). For example, if you have 60-cell panels, you’ll be able to expand with more 60-cell panels, regardless of make or model.

  1. Extra Installation Costs

When you purchase your system in installments, you end up paying a lot more in shipping and installation.

And if you’re working with a contractor, you’ll have to pay the same service fees twice. The labor always costs less if you can get the whole project done in one go.

But these surcharges are minor compared to the overall cost of the system. And it may be worth it to be able to break the purchase into installment payments.

And depending on your setup, you may be able to skip the contractor and handle any additions yourself.

The process for adding on new panels isn’t too complicated. It involves minor adjustments to the mounting hardware, like adding different clamps. Depending on the brand and frame size of your panels, you might be able to bolt it on to your existing hardware without any changes at all.

Do keep in mind that if you upgrade your system to produce more solar energy, you may also need to add another charge controller and make adjustments to your wiring so you don’t overload the existing circuitry. Electrical expansion can be complex and requires a healthy bit of knowledge and research or the aid of a certified electrician.

Our support rep Ricky learned first-hand that making wiring changes to his system was more challenging than it initially appeared. Read his story:

Going Off-Grid? Please Don’t Make the Same Battery Mistake I Did

Increased Energy Consumption

Sometimes your energy needs simply change over time, and you need to expand your system to keep up.

Did you install a well pump? Add a second refrigerator? Or maybe your household has grown recently  either new roommates or a new addition to the family  and you just need a bit more to cover the expanded usage.

In that case, you can add on to your existing solar system by purchasing more solar panels, inverters, or a battery bank expansion. It’s a great idea to talk to a DIY solar tech to understand which parts you’ll need to keep the system stable. If your current equipment isn’t on the market, they can recommend parts that are compatible with your current system.

Your Solar Panels Aren’t Producing Enough

If your panels aren’t putting out as much energy as you originally thought they would, the issue might not be related to the size of your system.

Other factors can contribute to lower energy output: temperature, shade, and the direction your panels are facing. Poor setup may cause an otherwise well-sized system to underproduce. In certain cases, reconfiguring your system can bring it up to its expected output.

Mounting Direction & Angle

If you live in the Northern Hemisphere, your panels should face true south. Facing panels directly into the sun during peak hours will maximize the energy you generate.

However, you can’t exactly change the orientation of the roof on a house you already live in. Many people have to settle for placement that’s “south-ish” or a split between east and west.

In this case, adding more panels is more cost-effective than trying to find the perfect orientation with your existing system. It doesn’t hurt to fine-tune your mounting orientation if you have an adjustable mount.

For a fixed tilt angle, your array should ideally be tilted at an angle approximately equal to your latitude, for optimal year-round production. If you use an adjustable pole mount, you can tilt to a steeper angle in the winter to optimize production throughout the year.

Realistically, it’s a lot of work to adjust mounts, and most people would rather leave it alone to avoid the hassle. But it is an option if space is limited and you need to squeeze that extra bit of efficiency out of your system.

Temperature & Location

Solar panels are rated at standard test conditions (STC). The tests are run in a controlled environment, with temperatures regulated to 77°F and an ideal amount of light shining down on the panels.

In reality, your living environment rarely matches these optimal conditions.

In fact, most panels produce about 10% less power than their rating due to heat, clouds, and other factors. A 300W panel might only put out around 270W on an average day. The maximum output is rarely achieved, except during clear sunny days with ideal conditions.

There is another rating system called PTC, which tries to account for real-world conditions. PTC ratings tend to give a more accurate picture of how panels will perform in the real world.

Before you size a system, take your local climate into account. Extreme climates translate into a larger knock on the rated efficiency of your system. Keep this in mind when sizing up an expansion for your solar array.

Shade

Solar panel production will be impacted by shade, and a few small shadows can have a big impact on your solar panel output. Solar panels need to be installed in full sunlight for optimal performance.

Some modern panels have features including bypass diodes and half cut cells that can help with shading. But if you are experiencing lower output, check to make sure the array is not being shaded throughout the day. Over time, it’s possible for trees to grow up and cast shade on your solar array, reducing its performance.

Also make sure your panels are clean from pollen, dust, leaves and other debris. Over time this can build up and start reducing performance if not cleaned off by rain and snow. Clean your solar panels with water and if needed, a small amount of mild detergent.

Aging Equipment

Over time, solar equipment will age and and drop in efficiency. Solar panels usually last for 30+ years, but the output decreases slightly every year. Most solar panels are guaranteed to produce 80% of their rated power after 25 years.

It could take years to notice the impact, but over time your panels and batteries will decline in efficiency. After 5-10 years, you may find that your production has dipped below your energy needs.

You should design your system to account for this efficiency drop. But if you didn’t take this into account from the start, it isn’t too hard to add parts to compensate for expected efficiency losses over the life of the system.

Adding To Your Off-Grid Solar Array

If you’re ready to move forward with an expansion, some of the easiest parts to add on to your solar system are the panels themselves. Most of the off-grid solar systems we sell have panels wired in strings of three. That means if you’re adding panels, you will do so in multiples of three (3, 6, 9, 12, etc.) – not one at a time.

Depending on your system, you may be able to add a few more panels to the existing charge controller(s). You could also install multiple charge controllers, but be aware: your battery bank can only handle a given amount of charge current. Eventually, if you add a lot of solar panels, you will have to upgrade your battery bank so that it can handle the additional influx of power.

Adding Panels To A Ground Mount

Because off-grid living is usually synonymous with wide-open spaces, many off-grid customers install a ground-mount system. Since you don’t have to climb on your roof to make adjustments, it’s very easy to bolt on new panels whenever you need.

This could work to your advantage if you plan to build your system over time. If you have the space, go with a ground-mount racking solution. You’ll have easy access to the system any time you need to make an addition or perform maintenance.

Adding Panels To A Roof Mount

In order to expand the solar array on the roof, you’ll have to add on more racking and connect the panels to the existing combiner box and charge controller, as long as it can carry the increased load of power.

Expanding a roof-mounted system can be a bit trickier, since space is limited. A portion of your roof may not provide a viable build space, if it faces the wrong direction or is covered in shade.

What happens if you run out of space on your roof?

The first option is to replace some modules with higher efficiency versions to bring you up to speed. If that’s not enough, you can also pair your solar array with an alternate power source like wind or hydropower. Be aware that these options are limited depending on access to local resources  it won’t be an efficient option in areas with low wind speeds or strong water currents.

Mixing and Matching Panels

Take care when mixing and matching old and new parts from different brands. As described in this article in Home Power:

“Solar panels have changed dramatically over the years…not that long ago, 80W 12V nominal modules were common; today, 200W (or larger)…are more typical.”

It is okay to mix and match panels, but make sure the new panels have the same or as close to the same operating voltage, watts, and amps possible.

For example, you could add a 270W panel to your existing array of 250W modules; both of these are 60-cell panels that operate at the same voltage. As long as the panel voltage is within 1 volt, the system will be fine.

Permitting & Code Compliance

Additional permitting may be required when you expand your system. Depending on the size of your expansion, you may have to have the plans approved by the authority having jurisdiction (AHJ) – in most cases, the county or city planning department.

Build your system by the books to avoid headaches down the line. Download our Solar Permitting Cheat Sheet to ensure your system is up to code.

Even if you’re off-grid and miles away from civilization, it never hurts to have all of your permitting taken care of. If you or your neighbor ever sell or appraise your land, permits will be useful to prove the system is built within your property lines and up to code.

All panels and equipment should ideally be certified by UL to be permitted in the U.S. UL is an organization that ensures PV equipment passes rigid safety and quality standards.

More Inverter Power!

Most of the off-grid inverters we sell are “stackable,” which means you can nest multiple inverters together for increased power output. This is especially useful if your usage increases over time and you need more power on tap.

Adding another inverter isn’t always simple. The circuit breakers and wiring in your system likely aren’t designed to support another inverter. In some cases, the entire inverter system may need to be rewired. But if you anticipate expansion when you build your system, expandable power centers are designed for this purpose. You can add extra inverters and rewire them to a central hub — no extra wiring necessary.

A bigger inverter may require a larger battery bank to handle the increased output. The inverter manual should indicate minimum battery bank size, typically 200-400 amp hours minimum per inverter.

Expanding Your Battery Bank

The process for expanding your battery bank depends on the type of battery you have – either lead acid or lithium.

When you add a new lead acid battery into an old bank, the new battery takes on the capacity and other characteristics of the existing batteries. When you add more batteries, they drain down to the level of the old ones.

This might not be a big deal if the battery bank is only a year old. But it’s usually it’s not a good idea to expand a lead acid bank after it’s been used for a several years. Simply put, your new batteries won’t hold as much power as they could when you mix them with older batteries.

This is one area where we recommend planning for extra capacity to future-proof your system. With proper maintenance, you can extend the life of lead acid batteries to 7-10 years. You don’t want to tack on more batteries halfway through and instantly have the new batteries run at sub-optimal efficiency.

You can increase your battery capacity by wiring in more batteries in a parallel circuit. A parallel circuit combines the positive and negative battery connections, to increase the current (in amp hours) while maintaining the same voltage.

Diagram showing series wiring versus parellel wiring

However, there is a limit on the number of lead acid battery strings that can be wired in parallel. Three parallel strings of batteries is the recommended maximum. One or two is more ideal: they will charge and discharge more evenly, which makes them last longer.

Lithium battery banks are easier to expand because there are built-in electronics to manage the battery charge and balancing. Certain off-grid lithium batteries can be expanded over time, including Simpliphi and Discover AES batteries.

If you’re pre-arranging your system for future expansion, lithium batteries are the more modular and expandable option.

They are also more efficient, safer and tend to last longer – which comes with a price premium, of course.

If you’re not sure where to start with your system expansion, our design techs can help you sort it out. Get in touch with a system designer to help ensure your upgrade is compatible and covers your increased energy needs.

Ground Mount vs. Roof Mount Racking: What’s the Best Way to Mount My Solar Panels?

Ground Mount vs. Roof Mount Racking: What’s the Best Way to Mount My Solar Panels?

courtney
COURTNEY JOHNSTON, Purchasing Manager at Wholesale Solar​

Once you have your solar panels picked out, it’s time to decide which mounting system is best for your living space, budget, and energy needs.

There are two types of solar mounting options: roof mount and ground mount racking systems. Roof mount systems affix to brackets on your roof, while ground mount systems are built into a foundation at ground level. See the comparison images below for examples.

Ground Mount

Roof Mount

There are benefits and drawbacks to each, and both mounting systems have their merits depending on your project specs. This article will dive deeper into what we think about when we recommend ground mount vs. roof mount racking to our customers.

But first, a quick summary:

Ground Mount Solar Racking

Pros

  • Easy to access
  • Easy to clean
  • Easier to troubleshoot
  • Stronger racking overall
  • System is not confined to the dimensions of the roof
  • Cooler panel temperatures means higher energy output
  • No need to remove panels if roof is replaced

Cons

  • Installation is more labor intensive
  • Installation is more expensive
  • Requires more parts and pieces
  • Permitting process is more expensive
  • Takes up real estate
  • Not aesthetically pleasing to everyone

Roof Mount Solar Racking

Pros

  • Less expensive
  • Requires fewer materials to install
  • Installation labor cost is lower
  • Utilizes unused space
  • Easier to permit

Cons

  • Hard to access – especially if your roof is steep or slippery 
  • Harder to troubleshoot errors
  • Higher panel temperatures mean lower panel output
  • Space constraints on the roof limits the size of the system
  • Can be a hassle if you need to replace the roof within the panel’s lifetime (might install the system twice)
  • Putting holes in your roof could lead to water damage

Why Go Ground Mount?

The Perfect Alignment

No matter what kind of solar system you’re considering, this much is true: every solar array works best when it’s able to get as much sunlight as possible.

If you live in the United States, you’re north of the equator, so the sun leans south as the Earth orbits. Facing your array true south will capture the most daylight and produce the best results. However, if you live south of the equator in South America, it would be more efficient to face your system true north.

Getting the perfect alignment can be a little tricky for a roof-mounted system. It isn’t likely that your roof naturally faces directly into the sun.

Ground-mount systems can face any direction you want. You can align your system at the optimal angle so it points directly at the sun. For that reason alone, ground-mounted systems are most efficient, as they maximize access to the sunlight that powers the array.

Benefits for Off-Grid & Grid-Tied Consumers

The perfect angle isn’t the only thing that makes ground-mount arrays more efficient. Being raised off the ground allows for better airflow and cooling, which means your panels produce more energy.

Most solar panels are tested at an average of 77° Fahrenheit – a normal sunny day, but nothing too extreme. But when it gets hotter than this, and the panels grow less efficient, producing 10-25% less electricity. The semiconductors suffer greater resistance to the flow of electricity. Think of it like squeezing the hose when there’s water running through it.

Proper airflow and cooling keep your panels running in optimal conditions, which is a clear advantage for ground-mount racking.

Giving You Room to Grow

If you’re installing on your roof, chances are you’ve got limited space to make the most efficient array possible. Should your energy needs change in the future, it could be challenging to add more panels to your current system.

When you go ground-mount, you’re under no such restriction – assuming you have the space in your yard. You can expand your array after the initial installation, and many ground mount racking options allow you to bolt on new additions easily.  

This means if you add on to your property and require more power, or if you find that your initial power supply just isn’t cutting it, you can add more panels as needed with minimum fuss.

Accessibility 

Another major benefit to ground mounted solar is accessibility. Solar systems require a lot of trial and error, especially in the installation phase. It’s a pain to have to get up on the roof every time you need to work out a kink with your system.

This is an even bigger selling point if you’re considering a system with microinverters and optimizers. With those accessories, there is a component under each solar panel and they can be difficult to replace on a roof-mounted system.

What happens if a microinverter in the middle of the array breaks down? In that case, you would have to remove several panels to access the source of the problem. When your system is on ground level instead of high up on the roof, it’s easier to troubleshoot panels and accessories.

Ground mount also makes it easier to clean your panels and perform routine maintenance on them. It provides you with more peace of mind to know you won’t have to risk your safety every time you need to brush snow off the panels, wash off dust and pollen, or remove debris from under the panels. There are also pole mounts available, which are ideal for heavy snow areas. Pole mounts can be constructed with adjustable tilt angles to maximize energy production and easily shed snow in the winter months.

Drawbacks Of Ground-Mounted Solar

Now for the drawbacks of ground-mount racking that you might want to consider.

In general, a ground mount is a lot more complicated to install and requires more money upfront to get the job done. If your primary concern is seeing the maximum return on your investment into solar panels, roof mount could be the way to go. The permitting process will be lengthier for a ground-mount system. And it will take up more space on your property, which you may prefer to use for something else.

More Labor Intensive & Requires More Cost Upfront

The main reason why a ground mount requires more cost upfront is because the system requires more parts to be assembled.

Think of it this way – when you place a solar array on the roof, half of the structure has already been built for you. But when you place a solar array on the ground, you have to build a sturdy roof-like structure to hold the panels in place.

This process involves getting your soil surveyed to make sure it can hold the system firmly in place, digging large holes, and paying extra for parts to build a suitable foundation for the panels.

Roof-mounted systems skip a lot of these costs. Assuming your roof is in good shape and doesn’t have structural damage, it should be strong enough to support the weight of the solar array. You don’t run into any of the hassle of building a brand new foundation to hold the panels in place.

Ground-Mount Racking Requires a Longer Permitting Process

Additionally, the city or county you live in might have a heavier hand in the installation process, since the system is considered a new structure. Depending on where you live, you will have to go to the authority having jurisdiction (AHJ) and obtain a building permit.

This will add extra challenges to the process. You’ll need to:

  • Submit a design plan
  • Consider soil type and property line setback requirements
  • Pay permitting fees

Ground-Mount Takes Up Real Estate

The final drawback to ground mounted solar is that it takes up a lot of space on your property. When you mount a system on your roof, it will be more discrete, and you get to keep the space on your land to do whatever you please.

The space issue isn’t a big deal if you have a large property. People who live out in the country tend to be able to find space for a ground-mounted system that won’t interfere with how they live the rest of their lives.

But if you own a smaller property, your roof may be the only place your solar array will fit. In some cases, a ground-mounted system isn’t even an option.

If space isn’t an issue, the decision often comes down to aesthetics. For those that consider ground mounted solar an unsightly blemish on their land, there are some artistic or unique installation options out there, such as those featured below.

But for the most part, people are proud of their solar arrays because they are a cutting-edge technology that represents freedom from the power company and total independence.

We like it when people show off their systems with a sense of pride. But there’s nothing wrong with preferring one look over another. For buyers who have the luxury of space, the decision often comes down to whether they think ground or roof-mounted systems look better.

Key Points To Consider:

Go with a ground-mount system if you want to simplify the maintenance / cleaning process and maximize energy output over time. There are three main questions to ask yourself to make sure ground-mount will work for you:

How much are you looking to spend upfront?

A ground-mount racking system requires more labor and parts to install it. You may need to partner with a contractor to get the job done, and the permitting process will be lengthier and more expensive.

But consider this: once the panels are installed, the upfront cost will be offset down the line by a more efficient energy output. There’s also less cost and hassle involved if you have to remove the panels for re-roofing.

You’ll shell out a bit more cash at the start, but the effort will pay for itself over time.

What kind of soil do you have?

If your property is on bedrock or if you know the soil is going to be really difficult to dig into, you might want to put the panels on your roof. Hard soil can make installation costs for ground-mount systems skyrocket. It’s not impossible, but you’ll need to rent heavy-duty equipment to drill into the ground.

There are also a few workarounds with ground-mount options to keep the digging to a minimum. A ballasted system might be a good solution. Learn more about the different racking options available in our article covering frequently asked questions about ground-mount racking systems.

Will you need to expand your system?

If you don’t plan on living off-grid, a rooftop system will probably be more than enough for your energy needs. However, if you are planning to go off-grid, the ground mount will allow you to add more panels as your energy needs change over time and you will get the benefit of a built-in tilt that can face towards the sun more easily than your roof.

When is Roof-Mount Racking Better?

Neither mounting system is “better” than the other – the choice depends on how your budget, energy needs, and lifestyle come together. A roof-mounted solar system tends to be a better option for customers who:

  • want to maximize their ROI
  • want a system that is simpler to install
  • don’t have a lot of space
  • want to spend less money upfront

Less Materials & Labor Means Less Cost Upfront

One thing that makes a roof-mounted solar system an easy sell is that it requires less time and money upfront to install.

When you put a solar system on your roof, the most complicated part of the structure is already in place. You don’t have to dig holes, get the soil surveyed, worry about your property line, or purchase expensive materials like poles and concrete.

The set-up is ideal for grid-tie customers that want to make a smart investment; installing on the roof instead of the ground can save you thousands of dollars.

Makes Use Of Unused Space

More often than not, a roof mount is used in a residential setting where there isn’t a lot of space for a ground-mount system. You might live in a condo or tightly-packed suburb. What scarce yard space you have might be better used for barbecues or a place for the kids to play. Mounting panels on the roof allows you to use space that would otherwise be useless, saving the rest of your property for the things that matter most.

Even for people with lots of land, some choose to install solar panels on the roof because it’s more inconspicuous. It keeps the space on your property free for things like raising animals, farming, and outbuildings. Roof-mounted systems keep the clutter off your land, so there’s more room to get things done.

Added Insulation & Protection

One unexpected benefit to a roof-mounted system worth mentioning is that it protects the roof from degrading elements like UV light, wind, rain, and snow. It will also keep your structure more insulated. If you’re living off-grid, this can be a nice way to keep the house naturally warmer at night and cooler in the daytime.

According to this article from Earth Sky, students at UC San Diego found that solar panels kept the roof an average of 5° Fahrenheit cooler than an exposed rooftop, which saved the building an average of 5% on cooling costs. Those savings are on top of what you’ll save on your energy bill anyway by going solar.

Easier To Permit

Are you one of those people who doesn’t like to get tangled up in bureaucratic procedures? A roof-mounted racking system is perfect for you. It involves a much simpler permitting process. You can submit the blueprints for your home to show whether or not your roof is structurally sound, and you’ll have to make sure your wiring and electrical systems are up to code. This typically won’t be an issue unless you live in an old home.

There’s no extra design paperwork to submit, because you aren’t building a new structure on your property – something that would lead to a much longer approval process.

Drawbacks Of Roof-Mounted Solar

What makes people shy away from roof-mounted systems? There are a couple downsides to consider:

  • Inaccessible due to their height
  • Less efficient, depending on the positioning of your home
  • Harder to modify and troubleshoot
  • Space constraints on smaller rooftops

Accessibility Makes Things Harder To Troubleshoot

For anyone that’s ever installed Christmas lights or cleaned out the gutters on their home, you know what a pain it is to get up on the roof. Depending on your mobility and planned level of involvement in the installation process, you may want to consider the accessibility of your roof. Depending on the pitch and what kind of material your roof is made out of, you may not want to risk getting up there. For example, metal roofing is really slippery.

Less Efficient

Roof-mounted systems are rarely as efficient as ground-mount systems. Rooftop solar panels can’t always be aimed directly at the sun. It’s a lot harder to angle an array on an existing structure so that it is optimized for full power consumption during peak hours.

You’re at the mercy of the built-in specs of your roof, which means you can’t always get the panels facing true south (above the equator) or north (below the equator). To compensate, you may have to buy a few extra panels to match the output of a perfectly aligned ground-mount system.

Space Constraints

The average roof area on a standard, medium-pitch roof in America is 1,500 square feet. Some of this space will be unusable due to chimneys, vents, and other obstructions. There’s not a lot of space left to work with.

Once your system is in place, it will likely be impossible to add on to that system if you need to increase your energy production. If your family grows or you add an extension to your home, it could be challenging to add extra panels to adapt to increased energy consumption.

Key Points To Consider

If you think rooftop solar is the best option for you, be sure to consider some commonly overlooked questions:

How old is your roof?

A roof and a solar system have a similar lifespan, so it makes sense to install them at the same time. Roofs less than 5 years old will likely be fit for solar panels. Any older than that and you at least want to consider whether it’s a good idea to replace it at the same time you install the panels.

If your roof is really old, there may be damage, leaks or structural integrity issues to worry about. It will need to be in good shape to support the weight of the solar array. Try to anticipate roof repairs before installing your system. It’ll be a huge pain in the butt to repair your roof after the panels are installed.

Does your HOA have constraints on where you can mount your panels?

Depending on the solar access laws in your state, a homeowners association (HOA) can prevent you from installing solar panels. Before you purchase your solar system, check in with your HOA to see if they have any guidelines regarding solar. You can negotiate any problems with them while you get the permitting in order.

How expensive is your electricity?

Even though solar panels are an excellent investment, it requires a big financial commitment upfront and it can take time to get a return on that investment depending on your energy consumption. If your energy consumption is small, your savings will be too. A lot of those savings can depend on your state and whether or not you live in a remote area that has expensive electricity. So even though we are big supporters of solar, it’s not for everyone – it really depends on your core goals.

To discover your key goals and find the perfect solar system for your specific needs, download our Getting Started With Solar Guide.

5 Questions You Should Ask Before Installing Ground-Mount Solar

5 Questions You Should Ask Before Installing Ground-Mount Solar

courtney
COURTNEY JOHNSTON, Purchasing Manager at Wholesale Solar​

If you’ve read about the state & local incentives to go solar and maybe even looked into our free solar cost calculators, you’re likely convinced – going solar is a terrific investment. But once you’ve made the decision to purchase a solar system, that’s when the real questions begin.

If you’re a homeowner that has some acreage to spare, a ground-mounted solar array can be a terrific option for you. Depending on your budget, space, and energy needs, a ground-mounted system has a lot of benefits.

For starters, the system is easier to access and has no interaction with your roof – which means you don’t have to worry about damaging roofing materials, water leaking into your home, or moving the panels around in the case of a roof replacement.

However, before you bust out the auger, consider these five questions inspired by a conversation I had with solar professional Brady Schimpf. In addition to being the Technical Marketing Engineer at Ironridge, a company that produces mounting hardware for PV solar arrays, Schmipf has a lengthy background in solar installation.

Aside from Schmipf offering up answers to these questions about rooftop solar, he also clued me in on five key things many people misunderstand about ground-mounted solar – and shed some light on major compliance & property line issues that can cause all kinds of costly problems after installation.

Question #1:  “What are the different types of ground-mount solar systems and how do I know which one is best for my needs?”

Standard Ground Mount

When most people think of ground-mounted solar panels, they think of the image on the left (as featured in our Dec 2017 install of the month). This is what’s called a standard ground mount – where several poles are placed in the ground, and a racking system is installed on top to hold the solar panels.

The process of building this kind of system is similar to putting together a fence. You would first dig several holes that are a few feet deep, then set the poles in, and fill them with concrete. This structure would create the foundation for holding your solar panels.

A notable feature of a standard ground mount is that the panels are “fixed” – this means the tilt angle and direction is permanent. While the main benefit of this is that it’s cost-effective and easy to install the downside is that there is little to no adjustability and it’s not ideal for areas with extreme snow.

While concrete piers are always the most practical and cost-effective foundation for a standard ground mount, there are alternative foundation options including ballasted, driven piers, and helical piles. These are mainly used for large commercial or utility installations, typically when the soil is too hard or rocky to drill into.

With a ballasted solar system, it’s basically a standard ground mount with an added feature – concrete footings that are above the ground. Driven piers look like a huge pole, and as the name suggests, it gets pile-driven deep into the ground using specialized equipment.

Helical piles, also known as Earth screws, look like a giant screw. They also require special equipment for installation, similar to the driven piers. Additionally, all three alternative foundation options require working with a Professional Engineer (PE).

Pole Mount Solar Panels

Aside from standard ground mounts, you may also consider pole-mounted solar panels. When I consulted solar professional Brady Schimpf, he explained that pole mounts provide some interesting solutions that might apply to your unique situation.

For starters, pole-mounted solar panels are built in a similar way as the standard ground-mounted systems, but instead of digging several holes you would dig one big hole and set a huge pole into it. Then, the solar panels are mounted on top with a built-in tilt and swivel feature that allows you to adjust the panels manually or set up automatic trackers to improve your solar output.

While this sounds pretty appealing, Schimpf reminds consumers that what it really comes down to is the cost per watt. He stated,  

“In a residential system it’s way cheaper and equally as effective to add more arrays [solar panels] than have the ability to adjust a smaller array.”

However, there are benefits to a pole mounted system beyond energy output – the adjustable feature also allows you to lift the array above the ground to clear foliage, snow, and other obstructions. The height combined with adjustability makes a pole mount ideal for those that live in snowy climates. On the downside, pole-mounted solar panels are a lot more expensive, require a big concrete footing, and the large pipe is hard to work with.

Question #2:  “Does ground-mounted solar have to be off-grid?”

Both grid-tied and off-grid customers can use ground-mounted solar panels. The decision to use ground-mounted solar instead of rooftop solar usually has to do with space. For customers that have some acreage to spare, using ground-mounted solar can be a great option – but if you’re living on a smaller lot, or want a quicker ROI, you might want to conserve space and make use of the real estate on your roof. Ground mounted solar systems tend to be more expensive and labor intensive, but can be more efficient at capturing energy thus saving you more in the long run.

Question #3: “What are some things I should consider before installing ground-mounted solar?”

Before you purchase a ground-mounted solar system, consider the fact that it’s usually a more complicated installation process than putting solar panels on a roof. When you have a roof installation, half of the structure is already built. All you have to install is racking and the solar array. However, with a ground mounted system, you essentially have to build the structure of the roof from scratch, so the solar panels have something to sit on.

When I posed this question to Schimpf, here’s what he had to say:

“[Aside from space] one important thing to consider is your soil type. If you’re not familiar with what it is, you can get a local contractor out to do an evaluation for a reasonable fee.”

And depending on where you live, this could be an essential step. Some cities, especially those with certain soil types, strict building codes, and high earthquake risk, will require you to get your soil inspected and approved before you can move forward with your ground mount design. In that case, a soil engineer would look at the soil to determine its type and make adjustments to the foundation size and requirements of the design.

Keep in mind that all standard ground mount racking comes pre-engineered for all 50 states, but certain conditions in your area like heavy wind and snow and certain soil types may require special designs.

The key point here is that depending on where you live, you might need to meet with a local engineer to get your system approved and built to city standards.

So what are the best type of soil for ground-mounted systems?

Schimpf tells us:

“Basically anything that doesn’t have tons of large rocks and isn’t a hard-pan type material [works] well. Ground-mount works well on almost any other type of soil – it’s only an issue if you get into that [situation] with large rocks in the ground. That’s where it causes problems – but there are alternate ways around that…It’s more costly, but if that’s what you have there are options.”

Some of those options would be the more complicated foundations mentioned above – like ballasted, driven piers, or helical piles.

Question #4: “Do I have to get my property line surveyed before installing ground-mounted solar?”

One of the smartest things you can do before installing a ground-mounted solar array is to get your property line surveyed. According to Schimpf, issues with property lines come up a lot – usually after you’ve spent thousands to install a ground-mounted solar system. He recalled one scenario where a consumer built their solar system too close to the property line and the whole system had to be taken down and moved a foot backward.

“It’s very important to go through that process and understand property line setback requirements because if you install without a permit and you put [the system] too close to the property line, that can be a huge problem if you try to sell your home or get a permit to do other work on your property. Down the road, this can come back as a big issue.”

Property line setback requirements will vary quite a bit depending on what state or county you live in. For example, this document from San Diego County names the property line setback for ground-mounted solar arrays at a minimum of 3 feet. However, this document from the Department of Energy Resources in Massachusetts recommends counties in the state enforce 20-50 foot property line setback requirements (located on page 8).

To save yourself a ton of money and a massive headache, be sure to contact your local authority having jurisdiction (AHJ), which will be either your city or county depending on who issues building permits. To get a permit, you’ll have to go through all kinds of documented processes, including submitting a site plan. If you need assistance navigating the bureaucracy, be sure to download our free permitting guide.

Question #5: “Are ground-mounted solar panels safe & legal in my neighborhood?”

As long as you install your solar system after obtaining a building permit and purchase code-compliant materials, it’s entirely safe and legal. PV solar panels are compatible with most types of land use and permitting is typically handled on a local level.

According to Schimpf, when you install a ground-mounted solar array, there is not as much concern about fire as there is when you install on top of a roof, but UL 2703 code compliancy is still important. UL 2703 is a building code that requires PV solar racking materials, bonding, clamps, etc. to undergo rigorous testing that ensures they have the appropriate structural capacity, can withstand both high surges of electricity and don’t accelerate house fires.

And while the fire hazard element is more critical for rooftop solar panels, you still want to look out for UL 2703 compliant parts and avoid mixing and matching parts from different suppliers, as these parts may not have been tested together on a system level. Additionally, Schimpf recommends you protect the wires coming down from your solar array; they should be enclosed by a channel or raceway so that they’re not left open and exposed causing potential hazards.

Click to download our guide to getting started with solar power
Customers’ Biggest Questions About Rooftop Solar Panels Answered

Customers’ Biggest Questions About Rooftop Solar Panels Answered

courtney
COURTNEY JOHNSTON, Purchasing Manager at Wholesale Solar​

According to data from Consumer Reports, more residential homeowners are opting for solar power than ever before. From 2010-2015 the number of residential solar PV installations increased dramatically.

I surveyed three consumers who recently made the switch from PG&E power to sun energy, and they all said the same thing – their biggest concern during the purchasing process was their roof.

Many residential customers don’t have space for a ground-mounted solar power system. However, if your biggest concern is saving money and getting a quicker return on your investment, rooftop solar panels are likely the best fit anyway.

A rooftop installation is always more cost-effective because it takes advantage of an existing structure. With a roof mount, you don’t have to go out and buy pipes and concrete or pay for the extra labor it takes to install the system.

And although a rooftop solar system seems simpler at first glance, there are still a few important questions you might want to consider. In fact, here are the answers to five of the most common questions about rooftop solar power for home use.

Question #1: “Is my roof a good candidate for solar panels?”

Most residential customers considering the switch to solar power want to know whether their roof is even fit for solar in the first place. The truth is, solar panels can be installed on almost any type of roof – you just have to find the right mounting system for the job.

To get more information on mounting systems for rooftop solar, I spoke with solar industry expert Brady Schimpf, who is the Technical Marketing Engineer at Ironridge. According to Schimpf, “there [are] mounting systems for just about everything…but some are much more difficult, expensive, and labor intensive than others.” The first thing to consider before a roof installation is the material that the roof is composed of. The most common roofing material, composition shingle, is one of the easiest to install solar panels onto aside from a metal roof.

In general, solar panels are best installed on a sturdy roof that is made of composition shingle or metal, and things tend to be a bit more difficult on tile roofs – especially those that are so delicate that technicians can’t walk on them, like Spanish tile.

One technique an installer can use with a tile roof is to remove a section of tile and install shingles where the solar panels are going. This makes the solar system appear flush with the roof due to the raised height of the remaining tiles, and you won’t be able to see the shingle roofing underneath the solar panels.

Each type of roof will likely require a different style of mounting hardware, so if you plan on doing your own installation be sure to discuss those details with a solar consultant. For example, a low slope roof (a.k.a. flat roof most commonly seen on commercial buildings) can be tricky to install on, and typically requires hiring a roofing company to install flashings.

On the other hand, something like a metal roof can be much more straightforward. On certain types of metal roofs, a solar array can be clamped down without penetration, making it 100% leak-free. You might also check out this video about solar panel mounting options or this one below, which details how to mount solar panels to a roof step-by-step.

In addition to materials, customers should also consider the pitch angle of the roof, the size and shape of the roof, how much shading is present, the direction the roof is facing, and of course the age of the roof. All of these elements can affect how much solar energy your system is able to produce. If the system is installed correctly and optimized, it could potentially cover the cost of a new roof in energy savings in as little as 5 years.

Question #2: “Do I need a new roof to install solar?”

If your roof is in need of any major repairs, you will want to take care of them before you install your rooftop solar system. Solar energy systems have a lifespan of 25 to 35 years and taking a solar system down to replace a roof can be complicated and costly.

But generally speaking, this is only an issue for shingle roofs, which have the shortest lifespan. A shingle roof installed in the last 5 years is probably good to go for solar. For a roof that is older than that, consult a roofer to find out whether you need to replace the roof or perform major maintenance before installing solar panels.

Question #3: “Do rooftop solar panels damage the roof?”

One huge myth about rooftop solar installations is that it will damage the roof. On the contrary, a rooftop solar system can extend the life of a roof by protecting it from the elements.

Rooftop solar arrays are mounted slightly higher than the roof so air can circulate under the panels to prevent overheating. That being said, confirm that the technicians installing your rooftop solar system have experience with your particular roofing material and investigate whether the solar installation will void your original roofing warranty. Also, make sure you regularly clean debris like leaves and pine needles out from under the panels.

According to Schimpf, “Something a lot of new installers or DIY builders struggle with is damaging the shingles,” and the real issue with putting holes in your roof is the potential for water damage. As described by Schimpf, who has a long background in solar installation, technicians will install flashing underneath the shingles, and if they don’t take their time and lift the shingles carefully, it can damage the roofing materials making your home susceptible to water damage. Thankfully, much of those worries about water damage can be alleviated by some innovations in mounting hardware made in the last 5 years.

Schimpf described an elevated seal system produced by Ironridge that uses strategically placed metal flashing instead of rubber or sealant to divert water around the hole. This means homeowners would be reliant on an elevated piece of metal, which will likely outlast the home itself, over a rubber or sealant that has an unknown lifespan.

Question #4: ” Can I install a rooftop solar system by myself or do I need to hire an expert?”

Depending on your skill set, you can install a solar array on your own or partner with a contractor. Some Wholesale Solar customers handle a majority of the project on their own but hire contractors for some of the work. For example, you might want to pay a roofing company to install the flashings and then you can bolt on the rails and solar panels yourself. Any local roofing company can install flashings, and the company that installed your original roof will be able to verify that it won’t affect the original warranty.

Of course, doing everything yourself can cut down on the cost of your system and is perfect for a customer that wants to be highly involved with every step of the process. According to Schimpf, any DIY installer should try to find a mounting system that “goes together simply, has a low part count and is easy to put together.” Considering you’ll be working on an inclined surface, the less little parts you have lying around, the better. Schimpf compared the process to the “Ikea Cabinet Scenario,” where “you’ve got 60 different screws and fasteners, you’re trying to put it all together, and once the cabinet is assembled you realize you’ve got it all backward.”

Schimpf also noted an essential piece of information regarding fire code compliance. He recommended finding a mounting system that is UL2703 listed, which means it has been through rigorous testing to make sure it can handle large surges of energy, has the proper structural capacity, and won’t interact with the solar array to accelerate house fires. For more information on this and other key details regarding DIY installation, you can check out beginner to advanced webinars from Ironridge.

Question #5: “Where might I encounter hidden costs that decrease my ROI?”

When a customer asks how solar panels will affect their roof, they’re ultimately questioning whether they’re going to be faced with extra costs or headaches down the line. And this much is true – taking down and storing solar panels while replacing a roof can be costly.

One important point to make is that most solar systems have the same lifespan as the average roof, so as long as your roof is in good condition when the solar system is installed, you won’t have to take the solar panels down until it’s time to upgrade both the roof and your solar system.

So what does an expert on mounting hardware state as his biggest concern for rooftop installers?

“Keeping your roof membrane intact, keeping water out of your house… and taking the most time to make sure it’s done right.”

Some additional tips offered up by Schimpf involve commonly overlooked elements regarding mounting a junction box or rooftop conduit box. Customers should take the same precautions around water damage as is done with the solar array, otherwise, you’re really only completing half the job.

Additionally, be meticulous with your wiring. There will be cables that come down from every panel, and they need to be kept secure. If they’re drooping and blowing on the roof in the wind, the rough roofing material can wear through the insulation of the wire causing safety hazards. Also, as explained in this article by Mark Durrenberger from New England Clean Energy, unsecured wiring can provide a nesting location for small animals and collects debris more easily.

The wiring behind your panels can be secured using metal clips that keep everything tight and neat– just make sure the materials are made for solar use, like these metal clips from Ironridge. A cheap bag of zip ties won’t be able to withstand the elements in the long term.

So whether you’re ready to hop on the roof and install your own solar array or want to hire an expert, there are many design elements to consider. Some of the main takeaways are safety, the longevity of the parts used, and code compliance. If you’re ready to explore your options for residential solar, download our free getting started with solar guide.

 

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What’s the Best Off-Grid Solar Inverter?

What’s the Best Off-Grid Solar Inverter?

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By JOSH ROELOFS, Products Manager at Wholesale Solar

If you’ve spent any time researching solar energy, by now you’ve heard of an inverter.

The inverter is like your solar system’s brain. It manages your power flow, controlling two kinds of power.

DC—or direct current—power is the kind stored in batteries. It’s also the kind produced by solar panels.

But you can’t use DC power (directly) to power anything in your home. That’s where your inverter comes in.

Everything in your home uses AC—or alternating current—power. And an inverter takes DC power from your panels (or from batteries) and turns it into AC so it can be used for your fridge, lights, TV, and other household appliances.

Simple, right?

How IS an off-grid inverter different from a grid-tied inverter?

A grid-tied inverter takes DC power from solar panels, turns it into AC, and sends it into the grid for credit.

Grid-tied inverters are simpler and easier to wire since there are usually only two main components—the inverter itself and your solar panels. (Some grid-tied systems are starting to incorporate energy storage, but most don’t have any batteries at all.)

But an off-grid inverter needs a battery bank to function.

Here’s how it works: your solar panels feed DC power into the batteries. Then your inverter takes that power and “inverts” it, creating AC power for your home. This works essentially like a miniature power grid.

(In case you’re curious, no, your inverter won’t deplete your batteries provided your system is set up and designed right. The battery bank gets recharged by your solar panels and a charge controller, and by a backup generator in the winter months.)

As you might imagine, off-grid systems are more complicated, thanks to additional components like the charge controller, battery monitor, and additional AC and DC circuit breakers. All of these things tend to make off-grid systems more difficult to wire and install.

It can also be a challenge to buy off-grid equipment because there are a lot of associated accessories: remote controls, battery monitor, breakers and enclosures, surge suppressors, and so on.

Picking the right parts can be confusing enough—but there’s no more critical decision than buying the right inverter.

How to choose an off-grid inverter

Think About Size

The first thing to think about is how much power you need.

Fortunately, sizing off-grid inverters is straightforward if you know what appliances you’re going to use.

Add up the wattage of all your lights and appliances to calculate the number of watts you’d need if everything was used all at once. (No, you’re not likely going to use everything, but this is an easy way to be safe.)

Don’t forget to consider the voltage—although most appliances run on 120Vac, some appliances, such as well pumps, require 240Vac.

What’s the most popular size we sell? 4kW followed by 8kW. Different models and brands are available in various sizes and most of them can be stacked together for higher power output.

Consider Pure Sine Wave Instead of Modified Sine Wave

You may hear some manufactures talk about pure sine wave inverters. You don’t need to understand exactly how these work—it’s enough to know that the power that’s put out by a pure sine wave inverter is “cleaner” than what you’d get from a modified sine wave inverter.

Pure sine wave inverters deliver higher quality power output, similar to (or better than) our power grid. Modified sine wave inverters are cheaper, but they deliver lower-quality power output.

For this reason, modified sine wave inverters can cause issues with certain appliances. Motors, pumps and compressors run hotter and wear out more quickly. Certain sensitive appliances like computers can be damaged, or they may not work at all. These inverters also typically cause background noise on a stereo, and reduced video and audio quality for certain TVs.

That’s why we don’t recommend modified sine wave inverters for most applications; most of our off-grid customers are use pure sine wave inverters to avoid these potential issues.

Need a quick way to tell the difference? Look at your inverter’s total harmonic distortion (THD) rating. THD is an indicator of power quality output and will be listed on the spec sheet of any decent inverter.

Look at the Technical Specs

Here are some other technical specs to consider:

  • Efficiency. This is a measure of how much power from the batteries your inverter delivers to your home when it’s operating in perfect conditions. A good peak efficiency rating is around 94% to 96%.
  • Self-consumption, or no-load current draw. How much power will your inverter consume just sitting there? Obviously you want this to be as low as possible.
  • Surge capacity. How much short-term overload can the inverter handle before it “trips?” Some appliances, like pumps or fridges, need as much as 2x–3x their running power to start up.
  • Battery charger output. Many off-grid inverters include a battery charger, which is used to recharge your batteries during the winter months with a backup generator. The battery charger will have a rating, usually measured in amps. Most decent off-grid inverters will have a battery charger in the range of 50-100 amps DC.
  • Temperature range. Inverters are sensitive to extreme heat. Pay careful attention to the temperature range if you plan on installing your system in your garage or anywhere it could be exposed to temperature extremes.
  • Warranty. Warranties start at 1 year and typically range from 3-5 years, with a few manufacturers offering a 10 year warranty extension option.

You can normally find information on all these features on the product spec sheets. Check with your solar tech for help comparing and picking the right inverter.

Research Features

Your inverter may need special features. Look into these ones:

  • Battery charger. A charger allows your system to be charged from a backup AC generator. Most bigger inverters include this; these are called “inverter/chargers.”
  • Grid-tied capability. Some off-grid inverters have the added capability of feeding power into the grid, here are a few examples:
    • Outback FXR/VFXR
    • Outback Radian
    • Schneider XW+
    • SMA Sunny Island

    This capability is useful if the grid becomes available in the future, or if you are setting up a grid-tied system with battery backup.

  • Automatic generator start. Usually you’ll need an add-on accessory for this, although some inverters or charge controllers can take care of it.

Read Up on the Manufacturer

Knowing about the inverter manufacturer is also important. Check into their history and reputation. Off-grid inverters need to be on all day, 365 days a year, for several years at a time—so you’ll want to choose one from a manufacturer with a reputation for reliability.

In our experience, there are only a handful of companies making high quality inverters for this purpose:

Make Sure it Has UL Listings and Certifications

Off-grid inverters have a few different certifications required in the US, for safety and also to ensure code compliance.

Inverters for your home need to be UL 1741 listed. Mobile inverters for boats and RVs should carry a UL 458 certification. There are a few other requirements for different applications such as UL 1778 for uninterruptible power supplies and KKK-A-1822E standard for emergency services, such as ambulances.

There are other standards required outside of the US such as CSA 107.1 in Canada and IEEE 1547 used internationally outside of North America.

Don't Forget Price!

You also need to look at the price of the inverter system (including all required components)—as well as the features you get for that price.

Make sure to compare the price of all required components, including the remote control, circuit breakers, mounting plate, and anything else required to install the system.

Another Good Option: Using a Pre-Wired Power Center

A power center is a pre-wired off-grid inverter system that includes everything you need: an inverter, charge controller, remote control, and circuit breakers.

Most of the power centers we sell also include some additional components for monitoring and protection, including a battery monitor, and surge suppressors.

We assemble power centers with all of these components, and then wire them up and test on our workbench to make sure the system is wired correctly and working.

Buyers, especially those looking to DIY, love power centers because you can add them to a solar installation by making only a few final connections. (We even label the connection points to help make it even easier.)

So... What's the Best Off-Grid Inverter?

Your choice of inverter really depends on your size requirements and the application, but here are some of our favorites:

Our Pick For: Best Small Off-Grid Inverter

Morningstar SureSine

  • 300 watts 120Vac output
  • 12Vdc battery bank

This inverter is small. At just 300 watts of output power, it can handle lights, charging phones and tablets, and an efficient TV—and that’s about it.

But the SureSine is renowned for being extremely durable. It’s also used for industrial applications, powering remote equipment in harsh conditions all over the world.

It’s efficient, with very low self-consumption, which makes it ideal for smaller systems like a hunting cabin.

It’s also perfect for industrial remote power systems that require a small amount of 120Vac power.

Our Pick For: Best Off-Grid Inverter for Cabins & Small Homes

Magnum Energy MS-PAE

  • Two models: MS4024PAE and MS4448PAE
  • 4kW-4.4kW 120/240Vac output
  • 24-volt or 48-volt battery bank

The MS-PAE inverter series comes in two sizes: 4kW 24-volt, or 4.4kW 48-volt.

Magnum Energy inverters are fairly easy to set up and use. They have good surge capability and powerful battery chargers. They also have a nice Magnum Panel system that includes a back plate and breaker panel (to make a complete power center).

Installing these inverters on a Magnum Panel bumps up the standard warranty from three years to five.

There are accessories available, including a battery monitor, automatic generator start (AGS) and MagWeb kit for remote monitoring.
MS-PAE Magnum Power centers have been our best selling power centers for years, both for off-grid cabins and for small homes.

Multiple MS-PAE inverters can be stacked together—up to 4 inverters, or 17.6kW total—which makes this inverter also suitable for bigger off-grid homes.

The 4kW 24-volt model can work with smaller battery banks and solar arrays; that’s ideal for cabins.

Magnum inverters are available in a wide range of sizes, and they are relatively affordable and easy to set up, which makes them a great choice for off-grid cabins and homes.

Our Pick For: Best Large Off-Grid Inverter

Schneider Electric XW+

The XW+ inverter comes in two sizes: 5.5kW or 6.8kW output power. Both work with a 48-volt battery bank.

Multiple inverters can be stacked together, and groups of three can be combined for three-phase power systems.

Schneider offers several accessories including a power distribution panel, automatic generator start, and battery monitor. The Schneider XW+ system really excels with bigger, multi-inverter systems.

Schneider supports multiple clusters of inverters for large industrial and commercial applications, up to 102kW output power. They also support Lithium batteries.

All of these features, plus the ability to stack clusters of inverters, make the XW+ our choice for large off-grid power requirements.

BONUS PICK! Best Inverter for Grid-Tied Systems with Battery Backup

Outback Power Radian

The Outback Radian is an off-grid inverter that can also tie into the grid to sell your excess power.

This is the ideal option if you want the combination of battery backup and grid-tied solar, or if you’re off-grid but you think access to the grid will become available in the future.

The Radian inverter system includes advanced software, called Optics RE, for remote monitoring and control, allowing you to monitor your system, get alerts about any faults, and change settings remotely. It can also control generators for basic automatic start and stop.

Currently this is the only battery-based inverter approved for grid-tied interconnection throughout the US. It’s also the only grid-tied battery backup inverter available that complies with the newest standards in CA and HI for connecting grid-tied systems.

It’s available in two sizes, 4kW or 8kW, and multiple inverters can be stacked together for up to 80kW of power.

This is our best selling inverter for grid-tied with battery backup; most customers opt for either one or two of the 8kW inverters (either 8kW or 16kW.)

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7 Questions to Stump a Solar Salesperson

7 Questions to Stump a Solar Salesperson

What You Should Know Before Buying Your Off-Grid System

Choosing the right solar tech to install your off-grid system isn’t like going to a car dealership. Don’t get hassled or let yourself get hustled by sales tactics and industry jargon. Today, we’re giving you a few insider tips, so you’re in the know.

These 7 questions show you’ve done your homework before going solar, and they cover info every solar technician should know – so if yours can’t answer them, that’s a big red flag!

Save yourself some time and money with these 7 head-scratchers:

1. Does the number of cells in a solar panel matter?

Yes, because most Off-Grid Charge Controllers are optimized to handle voltage from 60-cell panels. There are charge controllers engineered to control the voltage demands of a 72-cell panel system, but they require pricey components and are not cost effective for most consumers.

panel-cells

 So what happens if you use a 72-cell panel system on a charge controller designed for 60-cell panels?

You could fry your charge controller! 

Make sure your solar technician knows your needs. Your charge controller and solar panel cell count should be compatible when designing your system. Many of our off-grid customers prefer the Midnite Solar Classic 150 Charge Controller, which is perfect for 60-cell panels in your array, usually arranged into strings of 3 linked panels.

2. Will I see an ROI on my battery-based system?

Not likely. Off-grid is more about energy independence than ROI, by the time your solar system pays for itself you’ll most likely need to replace your batteries (every 7-10 years). 

Most off-gridders aren’t going off the grid for the long-term investment. They aren’t getting the benefits of net metering or the short payback period you’d get with a grid-tied system.

Off-grid tradeoffs include: 

  • Complete self-reliance and the freedom to “be your own power company.”
  • Not paying for power lines to be run from the utility provider to your property.
  • More options when buying land, with remote, off-grid parcels often being much more affordable.

3. Should I use a tracker with my panels?

While a sun tracker will boost your energy production, you could just install a few more panels instead and save yourself some money. 

A tracker introduces moving parts, and therefore additional maintenance and added cost to your solar power system that you won’t have with a stationary install, and the benefit they add rarely outweighs the price. 

The only time a tracker would make sense is if you have a shortage of space, and need to squeeze every single kilowatt possible out of your array. 

If your solar tech pushes a tracker on you without proper assessment, they’re probably trying to add to their commission.

solar-tracker

4. How close does my inverter need to be to my batteries?

Almost all 24v and 48v battery-based inverters should be installed within 10′ of the battery bank to avoid “voltage drop.” The further the battery bank is from your inverter, the more voltage bleeds off as it travels through the wiring. The closer you can get the equipment, the better (10′ being the recommended maximum distance away). 

Most packaged systems will come with a 10′ long inverter cable for just this reason. Any good solar tech should be planning your system’s layout with this in mind, so it’s a good thing to check when laying out the installation.

5. Do I need the most efficient panels out there?

Don’t let your solar tech upsell you on the “most efficient” solar panels on the market! Most panels on the market today are going to offer you the wattage output you need and remain cost effective. 

So why would you spend more money in the most efficient PV array?

You’d only want the most efficient array if you have limited surface array to mount it on. That’s when high-end modules such as those from SolarWorld would make sense. They produce a higher wattage output for around the same space requirement as competitors, but for an added expense.

Say you need a solar array to output 7 kW to power your home. Let’s compare two brands of solar panel, each with different wattage, pricing, and array coverage: 

  • 24 Panels at $350/panel (+)
  • 60 Cells per panel
  • 295 Watts per panel (+)
  • 433 ft² total array coverage (-)
  • $8400 total (-)
  • 7 kW output
  • 26 Panels at $275/panel (-)
  • 60 Cells per panel
  • 270 Watts per panel (-)
  • 456 ft² total array coverage (+)
  • $7150 total (+)
  • 7 kW output

If you buy the SolarWorld panels, your solar array will be 23 ft² smaller in size than an Astronergy array. This is great if you’re trying to save space, but even with two fewer panels, the SolarWorld array will cost $1250 more! If you have space (and in most cases, you will), then opt for the less efficient panels: you’re saving money without really losing anything in the process.

6. Does the type of solar panel I use matter?

Solar panels can be manufactured a few different ways: polycrystalline, mono-crystalline, SIG, thin film, etc. How the solar panel is manufactured rarely matters, but who manufactured it does.

All solar panels operate on the same fundamental principle: using silicon-based semiconductors to convert the sun’s energy into electric power. However, the top 5 or 10 manufacturers make a higher quality, more reliable product than the 50 manufacturers below them. Those bottom-tier brands produce the panels that people can buy on eBay for $100. If the price is that low, you’re definitely getting your money’s worth.

Bargain-basement panels use cheaper components and manufacturing techniques. Many cheap manufacturers skimp on quality to save a buck or two, and pass the “bargain” on to you, the consumer, but in reality, you’ll be paying the price as they degrade quicker and require replacement!

Low-end manufacturers also skip the UL listing required to permit these panels, as well, which will cost you even more if you can’t pass inspections and permitting requirements.

TL, DR: Don’t get swindled by sketchy sales techniques, and don’t be a cheapskate when it comes to buying better panels! 

7. How Do I size My Off-grid Inverter?

First, you’ll need to use a Solar Cost Calculator to figure out how much energy your home and appliances will be using. Pay particular attention to the stuff that’s always on such as your fridge, well pump, outlets, etc. Some appliances have a higher “surge current” when they’re initially switched on – often appliances with motors or compressors, such as your well pump. In this case, they may have special requirements, which can vary widely. We recommend you choose a 4kW inverter minimum and consider larger ones to handle excess surge current.

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I Rent My Home… Can I Still Go Solar?

I Rent My Home… Can I Still Go Solar?

4 Steps to Investing In Solar When You Rent or Lease Your Home

Do you rent or lease your property? Did you know you can still go solar?

While residential solar systems are normally associated with homeowners, you still have options as a renter or lessee, and you can still shave a chunk off your power bill and rely on renewable energy.

The trick is finding the right situation for your solar aspirations – most landlords won’t let you mount solar panels on the roof they own (and you rent from them), so sometimes you have to get creative.

Below are a few good solutions to going solar when you rent or lease.

1. Modular and Portable Systems

Some solar systems can be set up with little to no installation processes – no bolting racking to the roof or installing heavy ground-mounted poles.

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Lightweight, flexible panels from SunPower® can be a great choice for renters and travelers, easy to transport and set up quickly. 

There are also specialty solar kits that can install on your balcony railings, window ledges, and banisters, allowing you to make the most out of your apartment or home space, without needing to install. Some of these systems even qualify for the 30% federal rebate, so you might end up saving more than you expect! The Rolling Thunder RT-1000 is a great plug and play portable option.

2. Join A Renewable Community

Some communities, neighborhoods, or even full districts can be remotely tied into solar farms or other renewable plants which power their utilities.

It’s possible to sign up for programs such as these through your regular utility company, which will often pay out in credits on your power bill. There are also experimental solar communities such as New York’s Brooklyn Microgrid and California’s SolarShares program.

solar panels in the city
The Brooklyn Microgrid, NYC's renewable community project.

Renewable communities are taking off in a number of states, with some cities already onboard for 100% renewable energy, and many more on track to join them in the next 20 years. Burlington, Vermont is already completely run on renewable energy sources, the first city in the nation to do so! It was quickly followed by Aspen, Colorado and Greensburg, Kansas, with Georgetown, Texas on track to achieve 100% renewable status by the end of this year.

Other, bigger cities are pushing for their own renewable energy goals by the end of the decade, including San Diego, Rochester, and Grand Rapids. If the trend continues, finding a city to live in that’s 100% powered by renewable energy should get easier every year!

3. Play the Market

If you can’t put solar on your roof, you can invest in those who do! Investing your portfolio in one specific industry or sector can help you diversify your holdings and profit when that industry grows.

Tesla, SolarWorld, and Enphase are all publicly traded companies whose stock shifts when the market fluctuates, and with the right investment and stock broker, you can cash in when the market grows. You can also put your money in an Extended Trade Fund (ETF) – a less risky option that covers several companies at once and can be traded similarly to stocks. When the solar industry profits, you profit.

growth-market

Bonds are another potential source of investment, allowing you to invest in the long-term future of a particular project or company. The caveat is that these usually take far longer to pay off than stocks, so it’s best to be in it for the long haul if you invest in this way.

Investments in renewable energy will pay off, the industry is growing and new renewable projects are added every day. According to the most recent data, renewable energy is a growth industry poised to pay off bigtime by 2030, and that means 2017 is a prime time to put your money in the renewable market.

4. Baby Steps

If you can’t afford larger PV panels and the equipment that goes with them, you can still make an impact by going solar on a small scale. Solar chargers for your laptop, cellphone, and other small appliances can make a big difference, allowing you to use less power from your home or apartment outlets without the need for heavier equipment, permitting, or your landlord’s permission.

solar panels on a trailer
A portable solar charging station designed for charging electronics at camp.

There are a number of solar power systems that can hang on your balcony or windowsill, be used indoors (in a sunny window spot, for example), or that are portable for camping and hiking.

So you can see, it’s not impossible to go solar when you rent! You can still make a difference both economically and environmentally, even if your landlord won’t let you put solar panels on the roof. Going solar has never been easier, so choose the option that’s best for your situation.

Filing Solar Power Permits in 2017? Consider the Following Factors

Filing Solar Power Permits in 2017? Consider the Following Factors

this guide will help you get the latest information on solar permits

Here's What You Need to Know.

All of these factors are important to consider when permitting your solar system, and can help streamline your process. Take the time to consider these often-overlooked aspects so you’re not caught off guard! 

This guide is the perfect prep work to get you started on going solar, and can save you a ton of time so you can get your install going and claim your Federal Tax Credit before the 2017 tax season ends in December.

Geographic Location

Every state, and many different cities within them, has different permitting processes and requirements for homeowners looking to install solar. California is our go-to example for state requirements: cities in California have some of the strictest zoning, building, and fire codes, so chances are if you can meet their standards, you can meet any state’s standards. We recommend you check your local AHJ (Authority Having Jurisdiction) for full regulations.

Some things to consider with your location include:

  • Urban or Rural Property
  • Off-grid or grid-tied
  • Zoning regulations
  • Fire codes and building codes
  • Property lines and neighborhood restrictions

Residential or suburban areas often have stricter zoning and installation requirements than rural areas – and if you own several acres of land you can more easily accommodate different mounting types such as ground or Pole-Mounted systems. In some cases, you have more of a choice in the matter – if you’ve recently bought property that’s off-the-grid, it’s a much more affordable option to go solar rather than paying tens of thousands of dollars to run wiring out to your property. Factors like this can help make your installation decision easier, and will affect your permitting and engineering needs down the line.

Wind & Snow Loading

Areas with high precipitation or snowfall require some planning – solar panels can usually only bear a certain load weight – snow and debris can add up quickly during the winter, so it’s something to plan for. You don’t want to spend thousands of dollars just to lose your entire solar setup when the snow hits this winter.

Moreover, your local AHJ will have building codes that require new structures (such as a solar array) to meet the requirements of your environment, so check with the authority for specific requirements. Many authorities require at least 10-40 PSF (pounds per square foot) load-bearing on panels, and most panels are rated for much higher than this at around 150+ PSF. 

Engineering

Engineering your system is essential in some areas, with many AHJs requiring a “wet stamp” which means an engineer needs to review each individual project and sign off on it before approval. Some areas require that ground mounted arrays get soil engineering, where an engineer tests the soil properties to determine how the foundation should be engineered before they can approve your permits.

DIY solar kits tend to include components from a number of different sources and manufacturers, so getting the right approvals and permitting can add time to your install. Some companies aim to alleviate this, for example, IronRidge racking is engineered for all 50 states, and typically meets any local wind or snow requirements – your AHJ and any needed engineer or building code authorities will need to know this info. 

Equipment

Newer or more complex equipment can delay or complicate your permitting and install process. Grid-tied systems are usually the most straightforward, but a grid-tied battery backup system will be scrutinized more closely because of the complexity, and often the local inspector will have questions. Expect to be asked about your battery bank’s brand, model numbers, battery type, venting method, enclosure, and other details.

Sometimes this also happens with new technology. A few years back, a lot of inspectors were confused about SolarEdge since it is a unique inverter with DC optimizers on each panel. We heard a lot of questions from the building departments about sizing and system calculations. Today, SolarEdge is the #1 residential inverter in the US, and we don’t hear as many questions from inspectors about it. More recently, some newer systems, such as Tesla’s powerwall, require specially-authorized (and often very hard to find) installation professionals who have been certified to work with their equipment.

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