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Our offices will be closed Monday 5/25 for the Memorial Day holiday. We will resume normal hours Tuesday 5/26. Have a great holiday weekend!, email us at sales@wholesalesolar.com, or Request a Quote
Our offices will be closed Monday 5/25 for the Memorial Day holiday. We will resume normal hours Tuesday 5/26. Have a great holiday weekend!, email us at sales@wholesalesolar.com, or Request a Quote

STEP 3: Size Your System for Off Grid

How big should your Off-Grid system be?
If you are moving from a utility-connected home in the 'burbs' to an off-grid home in the boonies, you will have the opportunity (perhaps necessity) of downsizing your electricity usage. In order to calculate how large your home power system needs to be, run the calculator below TWICE. Compare and adjust your plans according to your budget and lifestyle.



Off-Grid System Sizing Calculator

This provides a rough estimate of your solar needs. For a more precise calculation, please give us a call at 1-800-472-1142.

Wholesale Solar Off-Grid System Size Calculator
1. What's the most electricity you might use in a month?

Look at your past electric bills and find the month with the highest usage (often summer or winter, depending on cooling/heating needs in your area). The bill should show you the number of kilowatt-hours (kWh) used that month. Put this number in the space to the right.

OR
Use the actual watt-hours per day at the end of your Load Evaluation Calculator OR (PDF). Multiply results by 30 (for a monthly total) and divide by 1000 (to convert watt-hours to kilowatt-hours).
2. What percentage of your house/business power do you want to generate with solar power? If you want to produce 100% of your electricity, put 100.
3. How many Peak Sun Hours do you get per day? Look at the Solar Map below to find this number. This gives you the annual average. If you will use your system during the winter, subtract 1.5 hours from the annual average to account for decreased sunlight during those months. This ensures your system will be properly sized to provide year-round power, even during darker months.
Minimum System Size:

Approximate Solar Panel Wattage:

Approximate Number of Solar Panels Needed:


For 30 Kyocera 140-watt solar panels to produce 4,200 watts..... 4,200 divided by 140(watts per panel) = number of solar panels needed.
NOTE: These figures are approximate and do not take into account the variable efficiency ratings of solar panels and off grid inverters. Please work with experienced Wholesale Solar staff to design a system which fits within your budget and can be expanded as needed.

SUN HOURS/DAY ZONE MAP
solar insolation map
How Many Sun Hours a Day Do You Get?

Zone 1      6 hours
Zone 2      5.5 hours
Zone 3      5 hours
Zone 4      4.5 hours
Zone 5      4.2 hours
Zone 6      3.5 hours

The hourly figure indicates the average (over the course of the year) amount of insolation (full sun hours) for these zones.  These figures are based on the yearly average; consequently, systems based on these figures will provide more power in summer and less in winter.  Winter figures for daily solar gain may be from 25% to 50% LESS than these average figures.

Load Evaluation Calculator

Wholesale Solar Load Evaluation Calculator
Appliance Quantity Watts
(V x A)
Mult. * 1.5 for AC conversion
Hours On per Day Watt Hours per Day


Total Watt Hours per Day:
Watts
Watt Hours Required Assuming Inherent Efficiency Loss:
Watts

Appliance
Watts
Appliance
Watts
Appliance
Watts
Central Air Conditioner NA
5,000
Electric blanket
200
Hedge trimmer
450
Electric Clothes Dryer NA
3,400
Shaver
15
Weed eater
500
Oven
3,000
Waterpik
100
1/4” drill
250
Hair Dryer
1,538
Well Pump (1/3-1 HP)
480-1200
1/2” drill
750
Dishwasher
1200-1500
Laptop
60-250
1” drill
1000
Coffee Machine
1,500
Plasma TV
339
9” disc sander
1200
Microwave
1,500
LCD TV
213
3” belt sander
1000
Popcorn Popper
1,400
25” color TV
150
12” chain saw
1100
Toaster oven
1,200
19” color TV
70
14” band saw
1100
Hot Plate
1200
12” black and white TV
20
7-1/4” circular saw
900
Iron
1,100
Stereo
10-30
8-1/4” circular saw
1400
Toaster
1,100
Satellite dish
30
Refrigerator/ Freezer**
Microwave
500-1500
Radiotelephone - Receive
5
20 cu. ft. (AC)
1411 watt-hours/day*
Room Air Conditioner NA
1,100
Radiotelephone - Transmit
40-150
16 cu. ft. (AC)
1200 watt-hours /day*
Vacuum Cleaner
500
LIghts
  Freezer
Water heater
479
100 watt incandescent bulb
100
15 cu. ft. (Upright)
1240 watt-hours /day*
Sink Waste Disposal
450
25 watt compact fluor. bulb
28
15 cu. ft. (Chest)
1080 watt-hours /day*
Espresso Machine
360
50 watt DC incandescent
50
Cell Phone - recharge
2-4 watts
Dehumidifier
350
40 watt DC halogen
40
MP3 Player - recharge .25-.40 watts
Blender
300
20 watt DC compact fluor.
22

* TV’s,VCR’s and other devices left plugged in, but not turned on, still draw power.

**To estimate the number of hours that a refrigerator actually operates at its maximum wattage, divide the total time the refrigerator is plugged in by three. Refrigerators, although turned "on" all the time, actually cycle on and off as needed to maintain interior temperatures.

Humidifier
300-1000
CFL Bulb (60-watt equivalent)
18
Video Game Player
195
CFL Bulb (40-watt equivalent)
11
Standard TV
188
CFL Bulb (75-watt equivalent)
20
Monitor
150
CFL Bulb (100-watt equivalent)
30
Computer
120
Heaters***
 
Portable Fan
100
Engine Block Heater NA
150-1000
Ceiling Fan
100
Portable Heater NA
1500
Can Opener
100
Waterbed Heater NA
400
Curling Iron
90
Stock Tank Heater NA
100
Stereo
60
Furnace Blower
300-1000
Cable Box
20
Clothes Dryer - Gas Heated
300-400
Clock Radio
7
Well Pump (1/3-1HP)
480-1200

* The daily energy values listed here are for the most efficient units in their class and the information was obtained from Consumer Guide to Home and the General Electric website.