A starting point. Home size is only a proxy for usage. If you have your bills, the panel calculator by bill is more accurate.
Typical electricity use by home size
From the U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey (Table CE4.1), average yearly electricity use per home:
| Home size | Yearly use |
|---|---|
| Less than 1,000 sq ft | 6,807 kWh |
| 1,000 to 1,499 sq ft | 9,404 kWh |
| 1,500 to 1,999 sq ft | 11,014 kWh |
| 2,000 to 2,499 sq ft | 12,177 kWh |
| 2,500 to 2,999 sq ft | 13,020 kWh |
| 3,000 sq ft or more | 15,493 kWh |
These are national averages, calculated as each size group's total electricity divided by its number of homes. Climate, an electric heat pump or water heater, a pool or an EV can move your usage far from the average.
A 2,000 sq ft house
With 12,177 kWh a year and 400 W panels, a 2,000 sq ft house needs about 19 panels (7.25 kW) in California and 21 panels (8.08 kW) in Texas. Change the state and size in the calculator to see yours.
Solar production per state: PVWatts, standard 1 kW roof system facing south at a 20° tilt with 14% losses.