Off-Grid Load Calculation Worksheet

Start by finding how many watts each appliance will consume. Do not add appliances that should be propane-fueled, such as cooktops, hot water heaters and electric heat. Then multiply rated wattage of each appliance by the number of hours per day, on average, that appliance runs. This gives the total watt-hours per day for each light or appliance. Do this for each and every appliance. The total for all appliance loads is the total watt-hours needed each day.

Figures below show some appliances commonly used in independent solar homes. Substitute your own daily hours for each and add other appliances not listed. Refrigerators come on and off on demand by thermostat, so running time per day is not known. A KILL-A-WATT meter will accurately test watt-hours used per day for any AC appliance up to 1875 watts.

Use the tables below to determine the total energy in watt-hours per day used by all the AC and DC loads in your system or download the PDF above.

1. List all DC loads in the table below and calculate the total watt-hours per day.
2. List all AC loads in the table below and calculate the total watt-hours per day.
3. Add DC & AC totals together to get TOTAL WATT-HOURS PER DAY.