Off Grid Solar Load Calculator

One of the most important things to do BEFORE going solar is to calculate the amount of electricity you are currently using. You will use this information to determine the size of solar power system you will need. Our Solar Load Calculator can help you calculate your system load. To learn more about estimating your average energy usage, go to: Electrical Load Evaluation Calculation and System Design Information.

Load Calculator Instructions:

  • Fill out each field for each appliance, if you are unsure about the wattage of your appliance, click on "Add Appliance From Load Chart" button to add that appliance from the list that we prepared for you, with estimated wattage.
  • Use "Add Appliance" to add an empty row, and the "X" button on the right to each row to delete that row.
  • You can save the calculation to your email by filling out the form underneath the Load Calculator and click on "Send" button. Fields marked with "*" are required.

NOTE: This calculator is intended for helping us design off-grid solar systems. If you need a grid-tie or utility interactive system, please contact our office for a quotation. For grid-tie systems, you will need to know the maximum amount of energy your home consumes during the year. For most people, this occurs during the summer months due to running an air conditioner. You can find this information on your electrical utility bill. If you have any questions regarding your utility bill, we are here to help! Contact us at (800) 383-0195 or windsun@solar-electric.com.


ApplianceQuantityWattsMinutes On/HourHours On/DayDays On/WeekAverage Watt Hours/DayMax Watt Hours/Day 



Total Average Watt-Hours/Day:
Total Max Watt-Hours/Day:
Load Chart
ApplianceWattsApplianceWattsApplianceWatts
Clock radio
1002
Coffee maker
105001
Clothes washer
42501
Electric clothes dryer
340001
Natural gas clothes dryer
30001
Dishwasher
180001
Dehumidifier
78501
Electric blanket
8001
Ceiling fan
12001
Window fan
15001
House furnace blower fan
90001
RV furnace blower fan
10001
Hair dryer
154001
Portable heater
125001
Clothes iron
140001
Microwave oven
1000150
Personal computer
25001
Computer monitor
15001
Laptop computer
5001
Home stereo
10001
Refrigerator (18 cubic ft.)
69024
Freezer (17 cubic ft.)
79024
Game console (XBOX 360)
13501
Hot plate
120001
Toaster oven
125001
20" LED flatscreen tv
2501
30" LED flatscreen tv
3501
40" LED flatscreen tv
4501
40" Plasma flatscreen tv
6001
50" LED flatscreen tv
6001
50" Plasma flatscreen tv
10901
60" LED flatscreen tv
7501
60" Plasma flatscreen tv
16501
Toaster
110001
DVD/Blu Ray player
3001
Vacuum cleaner
122001
Electric water heater (40 gal.)
500001
Satellite receiver or cable box
3501
1/3 hp well pump
36501
1/2 hp well pump
52501
RV water pump
10001
Compact fluorescent bulb (CFL)
2501
LED light
1501
30 watt incandescent bulb
3001
50 watt incandescent bulb
5001
60 watt incandescent bulb
6001
75 watt incandescent bulb
7501
100 watt incandescent bulb
10001
150 watt incandescent bulb
15001
Cable Modem or DSL
6024
Smoke Detector
5024
Air Conditioner (Window Unit)
1500012
Air Conditioner (Central AC)
3500012
1 hp well pump
105001