CALL US TODAY
Open M-F, 9-5 CST
How Many Solar Panels Do I Need? Panels for Your House by City
The average U.S. home needs about 6 to 10 kW of solar, or roughly 15 to 25 panels of 410 watts, to cover its yearly electricity. The EIA puts average household use at 10,791 kWh a year (about 899 kWh a month). How many panels that takes depends mostly on where you live: in NREL PVWatts runs, the same home needs about 15 panels in Phoenix but about 25 in Seattle.
Panels needed for the average home, by city
| City | Yearly output per 1 kW of panels | System size for 10,791 kWh/yr | 410 W panels (rounded up) |
|---|---|---|---|
| Phoenix, AZ | 1,767 kWh | 6.1 kW | 14.9 (15) |
| Denver, CO | 1,600 kWh | 6.7 kW | 16.5 (17) |
| Miami, FL | 1,554 kWh | 6.9 kW | 16.9 (17) |
| Dallas, TX | 1,510 kWh | 7.1 kW | 17.4 (18) |
| Chicago, IL | 1,308 kWh | 8.2 kW | 20.1 (21) |
| Seattle, WA | 1,095 kWh | 9.9 kW | 24.0 (25) |
Output is from NREL's PVWatts calculator (version 8) for a south-facing, fixed, open-rack array at a 20 degree tilt with the default 14% system losses. Household use is the EIA's 2022 average. System size and panel counts are our calculation: yearly kWh / output per kW, then divided by 0.41 kW per panel.
How to figure out your own number
- Find your yearly kWh. Add up 12 months of electric bills. If you only have one bill, multiply its kWh by 12, but expect seasonal swings.
- Find your output per kW. Use the table above for the nearest city, or run your address in NREL's free PVWatts calculator.
- Divide. Yearly kWh / output per kW = system size in kW.
- Convert to panels. System size in watts / panel watts. Round up.
Example: a Chicago home using 1,000 kWh a month (12,000 kWh a year) needs 12,000 / 1,308 = about 9.2 kW, or about 23 panels at 410 W. The same home in Phoenix needs about 6.8 kW, or 17 panels.
What if you only want to cover part of your bill?
Many homeowners start smaller. Half of the average home's use (about 5,400 kWh a year) takes roughly 8 panels of 410 W in Phoenix and 13 in Seattle by the same math. For off-grid or backup systems, size for the loads you actually need: a refrigerator, well pump, or a few circuits. See How Many Solar Panels to Run a Refrigerator? and Off-Grid Solar System Cost and Sizing.
Seasons matter
Yearly averages hide big monthly swings. In the same PVWatts runs, 1 kW of panels in Chicago makes about 159 kWh in July but only 57 kWh in December. Seattle drops to about 33 kWh in December. If you are off-grid, size for your worst month, not the yearly average. More on that in Do Solar Panels Work on Cloudy Days and in Winter?
What affects how many panels you need
- Panel wattage. Higher-watt panels mean fewer panels for the same system size.
- Tilt and direction. The table assumes due south at 20 degrees. See Best Angle for Solar Panels.
- Shade and losses. PVWatts' default 14% loss covers soiling, wiring, and similar losses. Shade from trees or chimneys can cost much more.
- Your usage. Electric heat, a pool pump, or an EV can push yearly use far above average. Start with How Many Watts Does a House Use?
In-stock panels for home systems
- Rich Solar MEGA 410: 410 W, 24V. 8 panels $2,799.99, 10 panels $3,399.99, 12 panels $3,999.99
- Rich Solar MEGA 400: 400 W. 8 panels $2,699.99, 10 panels $3,299.99, 12 panels $3,899.99
- Nature's Generator 410 W monocrystalline (4-pack): $1,999.99
- Rich Solar ground mount for MEGA 335/410: holds 1 to 4 panels, tilt adjusts from 18 to 45 degrees. $699.99
Browse all solar panels or complete solar panel kits.
Need help sizing? Call 1-888-855-7286. Send us 12 months of kWh from your bills and your zip code, and we will size the panels, inverter, and battery for you.
Solar panel sizing FAQ
How many solar panels do I need for my house? About 15 to 25 panels of 410 W for an average 10,791 kWh a year, depending on your location.
How many solar panels to power a house in a sunny state? About 15 in Phoenix for the average home, based on PVWatts output of 1,767 kWh per kW per year.
How many kWh does 1 kW of solar make a year? From about 1,095 kWh in Seattle to 1,767 kWh in Phoenix in the PVWatts runs above.
How many solar panels for 1,000 kWh a month? About 17 panels of 410 W in Phoenix and about 23 in Chicago.
Is the average home number the right one for me? Only as a starting point. Use your own bills, since homes in Louisiana averaged 14,774 kWh a year and homes in Hawaii 6,178 kWh, per the EIA.