Category: Solar Panels

What are the Best Solar Panels? (2018 Edition)

What are the Best Solar Panels? (2018 Edition)

BRENT HILTON, Senior Design Technician at Wholesale Solar​

How do you find the best solar panels for your system?

It’s not an exact science. “Best” will mean different things to different people.

You may care about efficiency and long lifespan. You might want to support American-made goods.

Or maybe you just want the cheapest one that works.

We’re going to put our two decades of system design experience to good use to bring you handpicked recommendations of the best solar panels on the market in 2018. And if you prefer your info in video form, we put one of those together too:

Best Solar Panels - 2018 edition

Before we go over our methodology, here’s a sneak peek at our picks. (Let’s be honest, you’re here for product recommendations, so we won’t make you scroll too far.)

Best Budget Panels:

Best American Panels:

Best Premium Panels:

Best Panels for Remote Applications:

Best Panels for Industrial Use:

How to Pick the Best Solar Panels for Your Project

There are a handful of factors that influence how good panels are. Here are the main things you should look at when you research solar panels:

Cost per watt

For most people, budget is the primary factor influencing decisions during the design process.

Panels come in all different sizes. Full-sized panels typically fall in the range of 275-400 watts, though there are also smaller panels for specialty off-grid applications.

The great equalizer is cost-per-watt. Divide the panel price by how many watts it outputs. You’ll get a “true” pricing number, which you can use to compare all panels on a level playing field.

Warranty

There are two different warranty categories – performance and workmanship.

The performance warranty guarantees your panels will work above their rated efficiency for the duration of the warranty. Most manufacturers promise their panels will work at or above 80% efficiency after 25 years.

25 years is the industry standard, but a few manufacturers offer longer performance warranties of 30 years.

Then there’s the workmanship warranty. This protects against manufacturing defects and other physical problems with your panels.

The workmanship warranty is shorter than the performance warranty. A generous workmanship warranty gives a great indication that the manufacturer knows they are putting out a reliable product.

The industry standard workmanship warranty is 10 years, with some companies offering 20-year guarantees.

Efficiency

A solar panel’s efficiency rating refers to the amount of sunlight the panel can convert into usable energy. 14-22% is an acceptable efficiency range for panels produced by major manufacturers.

This relates directly to the output of a solar panel (in watts). For example, a SolarWorld 290w panel is 17.3% efficient, while their 300w module is 17.89% efficient.

Temperature Coefficient

Solar panels are tested in ideal conditions. When manufacturers measure panel output, they perform tests inside a climate-controlled factory.

Obviously, the real world is going to introduce less-than-ideal conditions. During those sweltering days in the dead of the California summer, your system will lag behind its rated efficiency.

The impact temperature has on true panel output is the temperature coefficient. The coefficient measures how much efficiency is lost for each degree above or below ideal test conditions.

We’ll give an example in Celsius, because that’s what most manufacturers measure: energy loss per 1°C temperature change.

For example, let’s say a panel was tested at 45° C, but its current temperature is 55° C. If the temperature coefficient is 0.4% Wp (Watt power), you can multiply that by the difference in temperature (10° C). That panel is operating 4% below its rated efficiency on that particular day.

There are separate temperature coefficients for voltage, amperage, and wattage. Certain types of solar panels like monocrystalline can perform slightly better at higher temperatures.

The temperature coefficient usually isn’t the most important variable to focus on unless you are in an area that gets extremely hot. This is because heat reduces the efficiency of your solar panels, making them operate at a reduced output.

Company History

The longevity and reputation of the panel manufacturer play a part in our recommendations. What good is a warranty if the company goes out of business before they get a chance to honor it?

For that reason, we look at companies with a stable track record in the solar industry. Every product on this list is produced by a major manufacturer that we don’t expect to disappear any time soon.

UL Listed

Underwriters Laboratories is an organization that has been around for over 100 years. UL sets standards and performs safety tests to ensure products are safe for public use.

Solar panels must be certified to UL 1703 standards if they are being installed on your home.

What are the best solar panels on the market in 2018?

Without further ado, here are the best solar panels you can buy for a variety of applications. The info in this article is current as of 11/13/2018.

Best Value Solar Panels: Astronergy 325W

  • Cost: $195 (60 cents per watt)
  • Workmanship warranty: 10 years
  • Performance warranty: 25 years
  • Efficiency: 16.8%
  • Degradation: -0.7% / year
  • Temperature coefficient: -0.408% Wp
  • # of cells: 72
  • Cell type: Poly

Looking for panels that won’t break the bank? Astronergy makes the best solar panels you can get from a pure value perspective.

Of the major module producers, Astronergy has the lowest cost-per-watt panels we’ve found. Their 325W panel retails at $195 (at the time of publication), which shakes out to 60 cents per watt.

A few of our employees run their home systems on Astronergy panels, and we also picked them for the system that powers the Wholesale Solar flagship office.

Their 16.8% efficiency is very respectable at this price point, and the warranty is on par with industry standards.

Astronergy also sets their warranty program apart from other companies by offering third-party insurance. Should they ever go out of business, the warranty would still be valid from the third-party provider.

That’s more for peace of mind than anything. Astronergy is a part of one of China’s largest electronics manufacturers. We expect them to be around for a long time to come.

But the extra bit of insurance on the warranty coupled with the low price point makes these panels a popular choice.

Best American-Made Solar Panels: Mission Solar 360W

  • Cost: $275 (76 cents per watt)
  • Workmanship warranty: 10 years
  • Performance warranty: 25 years
  • Efficiency: 18.36%
  • Degradation: -0.7% / year
  • Temperature coefficient: -0.377% Wp
  • # of cells: 72
  • Cell type: Mono

Among the American solar panel manufacturers, Mission Solar is our top pick. They design and assemble high-efficiency panels in San Antonio, Texas.

With solar panels getting cheaper all the time, the price gap between imported and American panels has shrunk considerably. Imported 325W Astronergy panels now sell for 69 cents per watt, while American-based Mission Solar sells 360W panels at 76 cents per watt.

Compare that to the premium LG panels featured in the next section, which go for $1.57 per watt.

Looking at the price distribution, Mission Solar’s place in the market is clear. Their prices are competitive with imported panels, and they also give the high-efficiency models a run for their money on output (while blowing them out of the water on the price tag).

If you want to pick up some high-efficiency panels at a competitive price (and support American goods in the process), Mission Solar is the go-to choice. We recommend both their 305W (60-cell) and 360W (72-cell) panel, with the latter being the most cost-effective option.

Best Premium Solar Panels: LG 360W

  • Cost: $560 ($1.56 per watt)
  • Workmanship warranty: 25 years
  • Performance warranty: 87% efficiency after 25 years
  • Efficiency: 20.8%
  • Degradation: -0.4% / year
  • Temperature coefficient: -0.3% Wp
  • # of cells: 60
  • Cell type: Mono

LG doesn’t just make solar equipment; they’re one of the leading electronics manufacturers in the world.

We feature LG’s 360W panel in our premium packaged systems. They are super space-efficient, packing more output into a 60-cell panel than most 72-cell panels on the market are capable of producing.

Every solar project is different, and some people have the challenge of building a system in a compact space. For example, you may only have room for 10 panels on your roof. These LG panels will help you squeeze as much output as possible out of the limited space available to you.

They also have a long lifespan. At -0.4%/year, the degradation rate of these panels is 0.3% better than our featured Astronergy 325W panel.

That may not sound like a lot, but when you work the math out, it means LG panels will retain 7.5% more efficiency than Astronergy panels at the 25-year mark.

And LG’s solar panel warranties are a thing of beauty.

Where most companies aim for a 10-year workmanship warranty, LG covers the full 25 years.

On the performance warranty side, LG ensures their panels will still be 87% efficient after 25 years. That’s a stronger promise than the standard 80% after 25 years.

What are the best solar panels for off-grid systems?

We get this question a lot: is there any difference between panels for off-grid and grid-tie properties?

There is a bit of nuance to the answer.

The panels themselves can always work regardless of system type. There is no such thing as “off-grid panels” or “grid-tied panels” specifically.

However, panels must be paired with other components and sized accurately, especially in off-grid systems.

Historically, off-grid systems have used PWM charge controllers, which required that you match 12V solar panels with a 12V battery bank.

Now, most modern off-grid homes will use an MPPT charge controller, which can adjust the incoming PV voltage to work with almost any solar panel.

However, there are still string sizing considerations based on the panel and charge controller specs. All of the components must be supplied with the appropriate voltage and current. Batteries add another layer of complexity for off-grid systems, since the array must be sized to sufficiently recharge the batteries without overcharging them.

There are also a handful of panels that are designed specifically for off-grid applications:

Best Solar Panels for RVs / Mobile Applications

Solar is also a great solution for mobile applications like RVs and boats. But you’ll need smaller panels to work around any space constraints.

The solution for this is SunPower 50W and SunPower 100W flexible panels.

The lower profile helps you find the right configuration with limited space available. And since these panels can bend up to 30 degrees, they can flex around curved surfaces to make the most of the space you have.

These panels are lightweight, easy to install and perform well in low light. They’re built to adapt to rough and changing conditions that come with living life on the road.

At just over $2.50 per watt, they’re more expensive than traditional panels (even the premium LG panels). But it’s a fair tradeoff for a mobile-ready solar panel solution built to perform in harsh conditions.

Best Solar Panels for Small-Scale Industrial / Remote Applications

The last category we’ll look at is the best solar panels for small-scale remote applications.

These tend to be used to power remote equipment for a variety of industries:

  • Lighting
  • Telecommunication
  • Security & surveillance
  • Oil & gas
  • Water pumping
  • Traffic
  • Utility monitoring

A lot of times this equipment is in a remote location (like at the top of a mountain or floating on a buoy in the middle of a lake) and you need a small, self-contained system to keep it running.

We would recommend both Solarland and Ameresco, depending on the application. A few examples:

This represents the high end of the output range for 12-volt panels. Both companies offer a variety of 12V panel options ranging from 1W to 160W. Solarland also has 24V options, including one that goes up to 190W.

For certain industrial applications, you may need panels that are certified for use in hazardous locations. The SolarLand C1D2 (Class 1, Division 2) panels are your go-to choice.

There are 12V options at 45W, 60W and 150W, as well as a 140W panel that produces 24V:

These can also be used on RVs and boats, where you just want a solid panel with glass and an aluminum frame. If you don’t need the flexibility of the Sunpower panels, these are actually cheaper by about 25-50 cents/watt depending on panel size.

That’s it for our recommendations! We think these are the best solar panels you can get for your money in 2018, but prices and product configurations will change rapidly as technology improves.

As you do your research, seek out efficient panels from trusted manufacturers, and calculate the cost-per-watt so you can compare products on a level playing field.

If you follow these guidelines, you’re sure to find the right solar panels to power your system.

This article was updated on 11/13/2018. For our most current prices, take a look at the solar panels page in our shop.

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Why Are Solar Panels So Expensive?

Why Are Solar Panels So Expensive?

Courtney Johnston, Purchasing Manager at Wholesale Solar
COURTNEY JOHNSTON, Purchasing Manager at Wholesale Solar​

Over the long term, solar energy is the cheapest way to power your property. But it requires a significant up-front investment that slowly pays back over time.

Everyone loves the idea of saving money on energy bills. But when someone puts a quote in your hands for a system that costs more than a new car, you might start to have your doubts…

“Seriously, why are solar panels so expensive?”

We get this question all the time. Here’s our explanation:

1. Huge Markup on Turnkey Installations

Did you get a quote from a full-service solar company that installs their own equipment? If so, they’re probably marking up installation costs like crazy – as much as double the cost of materials. You can save a good chunk of money by installing it yourself or hiring an independent contractor for less.

2. 30% Federal Tax Credit

You get a 30% federal tax credit for going solar. Just know that whatever you pay, you’ll deduct 30% of the cost of your system and installation from your taxes. (Heads up; the tax credit is being phased out by 2022.)

3. Solar is an Investment

The initial cost of solar is high, but the money you save on electric bills pays for the system over time. The amount of time it takes you to break even is known as the payback period.

This is a significant concept for anyone trying to understand why solar is a smart investment, so we’ll explain it in more detail in this article.

4. It’s Fine to Start Small

You can always start small and cover part of your energy needs, then expand as your budget allows.

It’s hard to give a conclusive answer, since this is such an open-ended question. But we hear it most often from people who have quotes out with a turnkey installer.

A system that costs about $10,000 in materials, like this 6.6kW grid-tied system, might be marked up to $30,000 after installation costs from a turnkey provider.

Which explains why sticker shock is a common phenomenon in this industry.

So here’s our advice: the best way to save money on solar is to install it yourself, or hire an independent contractor to complete the installation at a fraction of what a turnkey provider would charge you.

If the up-front cost is still a concern, the next solution would be to scale back to a more modest system design and then expand on it as your budget allows.

Don’t Overpay for Installation

Most of the time when someone asks us why solar panels cost so much, they’re working from a quote from a turnkey installer (a company that offers an all-in-one solution to source the equipment and perform the installation).

Here’s the trick: the cost of equipment is pretty much the same wherever you go. The markup is in the installation.

Large installers have overhead costs. They have to cover labor, pay rent on their office, maintain a fleet of service vehicles, supply equipment, take out insurance, and so on…

All those operating costs get rolled into the charge of installation.

And the markup is obscene.

A typical installation might take a team of 3 laborers a full 8-hour day to complete. At $25/hr, that’s $600 in total labor costs. Add a bit more for tools and overhead, and the installer might spend about $1000 to send a crew to complete the job.

And yet…turnkey installers charge 1-2 times the cost of equipment to install it. If your equipment costs $10k, your final bill may come out to $20-30k once everything is bundled together.

Uh huh. You can see why we’re such strong advocates for DIY solar.

If you’re holding a quote from a turnkey installer, we strongly recommend you explore DIY as an option. Installing a solar system can seem scary, but it’s a lot easier than it looks.

We’ve helped thousands of people through the DIY installation process – take a look at the customer galleries in our Install of the Month feature for inspiration.

Don’t feel comfortable installing your own solar system? There’s a nice middle ground between DIY and turnkey: buy the system direct, then hire an independent contractor to install it.

Independent contractors tend to charge way less for installation. They should charge you 75 cents to a dollar per watt, which means you’d pay $5-6k to install the same system we used as an example above. You can see the value comparison of all three options in the chart below.

This is not to say that we fault turnkey installers for what they do. If you have a family or a demanding job, time is likely your most valuable resource. A turnkey solution is absolutely worth it if you can afford it and don’t have time to design your system yourself.

Just know you’re paying a premium for them to install the system, and that premium is awfully steep.

30% Federal Tax Credit Makes Solar More Affordable

If you live in the United States and choose to go solar, your system is eligible for a federal tax credit.

Today, that credit is 30% of your cost to go solar (which includes the cost of installation and equipment). However, it will shrink over time to 26% in 2020 and 22% in 2021, disappearing completely by 2022.

The tax credit is a reduction of the income tax you owe. For example, if you owe $3,000 in taxes but received a $3,000 tax credit on a $10,000 system, your tax liability would be $0.

If solar seems too expensive, keep in mind that 30% of your system cost will be refunded when tax season comes. However, that benefit will be phased out over the next few years. So if you want to claim the extra kickback on your taxes, you’ll have to do so sooner rather than later.

Understanding Payback Period

Even if you skip the installer, you’ll still spend a good amount of money on the system itself. That number can be a little bit scary without any context.

It’s important to think of solar as an investment with a payback period.

Solar saves you money in the long run by reducing or eliminating electric bills. Over time, the money you save on electricity adds up.

Your payback period is the amount of time it takes for your energy savings to pay off the up-front cost of the system. (Other factors, like tax incentives, also speed up your payback period.)

The formula for payback period is:

System Price ÷ Value of Electricity ÷ Annual Usage = Payback period (years)

(This is a simplified formula. It doesn’t take into account certain factors like energy cost inflation, which increases costs by about 3% per year, or the scheduled replacement of smaller parts, like the inverter.)

The system may be pricey up front, but it will provide more than enough energy to pay for itself. For example, panels are warrantied for 25 years, but our sample 6.6kW system may pay for itself after about 8 years of typical use. The final 17 years of ownership yields profit off your investment.

Learn more about how to calculate payback period and return on investment for your solar system.

Start Small To Trim The Cost Of Solar

You don’t have to offset 100% of your energy costs if your budget doesn’t allow for it. It’s always possible to start with a modest system and then expand later.

You can start as small as one solar panel and a single micro-inverter. Solar panels and micro-inverters are a 1-to-1 system, meaning each panel is connected to its own micro-inverter.

This configuration can be expanded indefinitely. We build modest systems like this all the time for people who want to offset a small portion of their energy, then add to it over time as budget allows.

If you want to take this approach, be sure to mention your expansion plans to your system designer / sales tech. Not all inverters and panels are compatible. Start with a long-term plan in mind and plan appropriately.

Conclusion

Solar can be expensive in the short term, but the incentives will save you plenty of money over the life of the warranty. And the return on investment improves dramatically if you skip the turnkey provider and install it yourself – or at least hire an independent contractor to do it for you.

Trying to figure out whether solar is right for you? Take a look at our guide to getting started with solar. It’s tailored for people who are just starting to research the solar energy landscape.

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Winter Maintenance Tips for Solar Systems

Winter Maintenance Tips for Solar Systems

Preparing Solar System for Winter

In January 2015, the East Coast was pummeled with a winter storm dubbed “Snowpocalypse,” and another winter is just around the corner. Winters are the most demanding time for solar power systems. In addition to the inclement weather issues we discuss below, people generally spend more time indoors using more electricity—especially those with electric heating.

However, if you take the proper precautions, you can be sure your solar energy system will function properly even during the harshest winter weather.

Your solar system doesn’t require any additional maintenance to run smoothly in snowy weather, but it may require your attention more frequently. Keep these simple tips in mind to keep your system operating safely all winter long.

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Solar Panel’s Cooling Effect

Solar Panel’s Cooling Effect

San Diego, CA-  The benefits of installing  solar panels on your home go far beyond the electricity produced. According to new research by the University of California at San Diego, the shade provided by a solar panel array will actually insulate your home from heat to the point of lowering cooling costs. It is estimated that these savings will result in a 5% discount on the price of the system over its lifetime.

The Jacobs school of engineering’s research team used thermal imaging cameras to analyze the difference in heat signatures coming from roofs with and without a solar array. On average, a building’s ceiling structure with a solar array turned out to be 5 degrees Fahrenheit cooler than buildings in the direct Sunlight. One would expect the shaded roof-tops to be cooler, yet the surprise came from how much cooler they turned out to be. In one study, a building was found to experience a 38% reduction in the amount of solar heat directly hitting the roof, indicating that savings can exceed the 5% estimate in the long run.

Your solar panels essentially act as roof shades, taking the brunt of the Sun’s heat.  Air between the panel and the roof helps dissipate this heat as most solar arrays are set up on a tilt. It was found that at night, solar panels also assist in preserving heat stored in the building, being an effective insulator in the winter.

Solar panels can be fastened to most rooftops with minimal perforation or structural interference. There is a wide range of racking and mounting hardware options available, and most of them can be installed by the homeowner or a general contractor.

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