How many solar panels to power a house?
20 panels of 400 W for the average US home, which buys 899 kWh a month (EIA) and sits in a place with 4.5 peak sun hours: a 7.6 kW system on 414 sq ft of roof. In Texas (5.3 hours) it is 17 panels, in a 3.5-hour state 25, in a 5.5-hour state 16. A medium UK household (2,500 kWh a year, Ofgem) in London needs 6 panels. The tables below cover smaller and larger homes, every US state and the three Ofgem household sizes in four UK cities.
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How many panels for a small, average or large US home?
The EIA puts the average US home at 899 kWh a month. The rows run from half of that to twice that; the columns are a cloudy, an average and a sunny place. System kW = daily kWh / (sun hours × (1 − 14%)); panels = kW × 1,000 / 400 W, rounded up. Each cell shows kW / panels.
| Home | kWh per month | 3.5 sun hours | 4.5 sun hours | 5.5 sun hours |
|---|---|---|---|---|
| 50% of average | 450 | 4.9 kW / 13 | 3.8 kW / 10 | 3.1 kW / 8 |
| 75% of average | 674 | 7.4 kW / 19 | 5.7 kW / 15 | 4.7 kW / 12 |
| Average home | 899 | 9.8 kW / 25 | 7.6 kW / 20 | 6.2 kW / 16 |
| 150% of average | 1,349 | 14.7 kW / 37 | 11.5 kW / 29 | 9.4 kW / 24 |
| 200% of average | 1,798 | 19.6 kW / 50 | 15.3 kW / 39 | 12.5 kW / 32 |
How many panels to power the average house in each US state?
The same 899 kWh a month at each state’s peak sun hours (NREL data, Unbound Solar table), with the state’s average residential price from EIA (June 2026). For a home that uses twice the average, double the kW and the panels; the 2,000 kWh a month guide has the same table at 1,000 kWh.
| State | Sun hours | System kW | Panels | Roof area | Price |
|---|---|---|---|---|---|
| Alabama | 4.6 | 7.5 kW | 19 | 393 sq ft | 16.4 ¢/kWh |
| Alaska | 3 | 11.5 kW | 29 | 600 sq ft | 28.21 ¢/kWh |
| Arizona | 6.5 | 5.3 kW | 14 | 290 sq ft | 15.18 ¢/kWh |
| Arkansas | 4.5 | 7.6 kW | 20 | 414 sq ft | 14.12 ¢/kWh |
| California | 5.6 | 6.1 kW | 16 | 331 sq ft | 34.74 ¢/kWh |
| Colorado | 5.5 | 6.2 kW | 16 | 331 sq ft | 17.13 ¢/kWh |
| Connecticut | 4.2 | 8.2 kW | 21 | 434 sq ft | 24.32 ¢/kWh |
| Delaware | 4.4 | 7.8 kW | 20 | 414 sq ft | 19.29 ¢/kWh |
| District of Columbia | 4.4 | 7.8 kW | 20 | 414 sq ft | 24.39 ¢/kWh |
| Florida | 5.3 | 6.5 kW | 17 | 352 sq ft | 15.1 ¢/kWh |
| Georgia | 4.8 | 7.2 kW | 18 | 372 sq ft | 16.36 ¢/kWh |
| Hawaii | 5.8 | 5.9 kW | 15 | 310 sq ft | 52.72 ¢/kWh |
| Idaho | 4.9 | 7 kW | 18 | 372 sq ft | 14.37 ¢/kWh |
| Illinois | 4.3 | 8 kW | 20 | 414 sq ft | 19.89 ¢/kWh |
| Indiana | 4.2 | 8.2 kW | 21 | 434 sq ft | 17.51 ¢/kWh |
| Iowa | 4.4 | 7.8 kW | 20 | 414 sq ft | 15.93 ¢/kWh |
| Kansas | 5 | 6.9 kW | 18 | 372 sq ft | 15.71 ¢/kWh |
| Kentucky | 4.3 | 8 kW | 20 | 414 sq ft | 14.26 ¢/kWh |
| Louisiana | 4.7 | 7.3 kW | 19 | 393 sq ft | 13.49 ¢/kWh |
| Maine | 4.2 | 8.2 kW | 21 | 434 sq ft | 29.59 ¢/kWh |
| Maryland | 4.4 | 7.8 kW | 20 | 414 sq ft | 21.84 ¢/kWh |
| Massachusetts | 4.2 | 8.2 kW | 21 | 434 sq ft | 29.61 ¢/kWh |
| Michigan | 4 | 8.6 kW | 22 | 455 sq ft | 22.99 ¢/kWh |
| Minnesota | 4.3 | 8 kW | 20 | 414 sq ft | 17.52 ¢/kWh |
| Mississippi | 4.6 | 7.5 kW | 19 | 393 sq ft | 14.88 ¢/kWh |
| Missouri | 4.6 | 7.5 kW | 19 | 393 sq ft | 16.22 ¢/kWh |
| Montana | 4.7 | 7.3 kW | 19 | 393 sq ft | 15.14 ¢/kWh |
| Nebraska | 4.8 | 7.2 kW | 18 | 372 sq ft | 13.25 ¢/kWh |
| Nevada | 6.4 | 5.4 kW | 14 | 290 sq ft | 13.11 ¢/kWh |
| New Hampshire | 4.2 | 8.2 kW | 21 | 434 sq ft | 27.01 ¢/kWh |
| New Jersey | 4.3 | 8 kW | 20 | 414 sq ft | 24.95 ¢/kWh |
| New Mexico | 6.5 | 5.3 kW | 14 | 290 sq ft | 15.06 ¢/kWh |
| New York | 4 | 8.6 kW | 22 | 455 sq ft | 29.49 ¢/kWh |
| North Carolina | 4.7 | 7.3 kW | 19 | 393 sq ft | 14.74 ¢/kWh |
| North Dakota | 4.5 | 7.6 kW | 20 | 414 sq ft | 14.12 ¢/kWh |
| Ohio | 4.1 | 8.4 kW | 21 | 434 sq ft | 19.19 ¢/kWh |
| Oklahoma | 5.1 | 6.7 kW | 17 | 352 sq ft | 14.33 ¢/kWh |
| Oregon | 4.2 | 8.2 kW | 21 | 434 sq ft | 16.32 ¢/kWh |
| Pennsylvania | 4.1 | 8.4 kW | 21 | 434 sq ft | 21.73 ¢/kWh |
| Rhode Island | 4.2 | 8.2 kW | 21 | 434 sq ft | 29.23 ¢/kWh |
| South Carolina | 4.8 | 7.2 kW | 18 | 372 sq ft | 15.55 ¢/kWh |
| South Dakota | 4.7 | 7.3 kW | 19 | 393 sq ft | 15.36 ¢/kWh |
| Tennessee | 4.4 | 7.8 kW | 20 | 414 sq ft | 14.07 ¢/kWh |
| Texas | 5.3 | 6.5 kW | 17 | 352 sq ft | 15.94 ¢/kWh |
| Utah | 5.5 | 6.2 kW | 16 | 331 sq ft | 13.37 ¢/kWh |
| Vermont | 4 | 8.6 kW | 22 | 455 sq ft | 24.44 ¢/kWh |
| Virginia | 4.5 | 7.6 kW | 20 | 414 sq ft | 17.22 ¢/kWh |
| Washington | 3.8 | 9 kW | 23 | 476 sq ft | 14.91 ¢/kWh |
| West Virginia | 4.1 | 8.4 kW | 21 | 434 sq ft | 15.45 ¢/kWh |
| Wisconsin | 4.2 | 8.2 kW | 21 | 434 sq ft | 19.56 ¢/kWh |
| Wyoming | 5.2 | 6.6 kW | 17 | 352 sq ft | 15.24 ¢/kWh |
How many solar panels to power a house in the UK?
Ofgem’s typical domestic consumption values for 2026 are 1,600, 2,500 and 3,800 kWh a year for a low, medium and high household. Sun hours are PVGIS daily irradiation at the optimal tilt, cloudiest city first. Each cell shows kW / panels.
| Household | kWh per year | Glasgow (2.88 h) | Manchester (3 h) | London (3.48 h) | Brighton (3.9 h) |
|---|---|---|---|---|---|
| Low | 1,600 | 1.8 kW / 5 | 1.7 kW / 5 | 1.5 kW / 4 | 1.3 kW / 4 |
| Medium | 2,500 | 2.8 kW / 7 | 2.7 kW / 7 | 2.3 kW / 6 | 2 kW / 6 |
| High | 3,800 | 4.2 kW / 11 | 4 kW / 11 | 3.5 kW / 9 | 3.1 kW / 8 |
What the tables leave out
- Your bill: every row is an average or a band. Twelve months of kWh from your own bills, divided by 12, typed into the how many solar panels do I need calculator (UK and US) beats any table here.
- Floor area: a 1,600 sq ft home (EIA band 1,500 to 1,999 sq ft, 11,009 kWh a year) needs 20 panels at 4.5 sun hours; the 2,000 sq ft cost guide sizes and prices every floor-area band in every state.
- Orientation and shade: the sun hours assume a south-facing array at a good tilt; east or west roofs get 15-20% less (Energy Saving Trust), and trees or chimneys more. Raise the losses in the calculator to see the effect.
- Money: the panel count is one line of a quote. The UK cost guide prices 6 to 16 panels and the payback calculator runs any size against your electricity price.
- Daily figures: if you think in kWh a day rather than a month, the 30 kWh a day guide runs 5 to 50 kWh a day in every state and UK city, with the same formula as the 20-panel answer above.
Sources
Average US use: U.S. Energy Information Administration, FAQ "How much electricity does an American home use?". UK household bands: Ofgem, "Review of typical domestic consumption values: decision", Table 1, electricity Profile Class 1, 2026 TDCV. US sun hours: Unbound Solar, "Peak Sun Hours by US State", table built from NREL's PVWatts data; "A peak sun hour is one hour of sunlight at an average intensity of 1,000 watts per square meter". UK sun hours: European Commission Joint Research Centre, PVGIS 5.2, PVcalc for the city's coordinates at the optimal slope and azimuth. Panel: A 400 W panel is the middle of the Trina Vertex TSM-DE09 range and the common residential class in 2026; Trina Solar, Vertex TSM-DE09 data sheet, product range 390-405 W. Losses: NREL, PVWatts Version 5 Manual, section 11 System Losses, Table 6. All read 2026-09-20; the full text of each source, with links, is under the calculator.
Frequently asked questions
- How many solar panels do I need to produce 30 kWh per day?
- 20 panels of 400 W at 4.5 peak sun hours: 30 / (4.5 × (1 − 14%)) = 7.75 kW, and 7.75 kW × 1,000 / 400 rounds up to 20. 30 kWh a day is 913 kWh a month, almost exactly the EIA average home, so the state table applies. Fewer sun hours mean more panels: 25 at 3.5 hours, 16 at 5.5.
- How many solar panels for a 1,600 sq ft home?
- 20 panels of 400 W (7.79 kW) at 4.5 peak sun hours, 26 at 3.5 hours, 16 at 5.5; in Texas (5.3 hours) 17. The EIA's 2020 survey puts homes of 1,500 to 1,999 sq ft at 11,009 kWh a year, 917 kWh a month or 30.2 kWh a day, almost the same as the 899 kWh average home, so the state table above applies. Your own bills beat the band average; the 2,000 sq ft cost guide prices every floor-area band.
- How many solar panels for a 4-bedroom house?
- No published figure ties bedrooms to kWh, so start from the bill. The largest household band Ofgem publishes is "high", 3,800 kWh a year: in London that is 9 panels of 400 W (3.5 kW). In the US a home using twice the average, 1,798 kWh a month, needs 39 panels at 4.5 sun hours. Take the kWh from twelve bills, divide by 12 and type it into the calculator.
- How many solar panels to power a house off grid?
- More than the tables show, because off grid the worst month has to work, not the yearly average. In London PVGIS gives 1.48 sun hours a day in December against 3.48 for the year, so a system sized for December is 2.4 times the size in the table, plus a battery for the nights. This site sizes grid-tied systems; an off-grid installer sizes to the winter load and the days of storage.
- How much does a system for the average house cost?
- At the US starting values ($2.60 per W, EnergySage) the 6.5 kW system for the average home in Texas costs $16,860 before any state or utility incentive; at 15.94 ¢/kWh it saves $1,720 in year one. The payback calculator runs the 25-year table for your quote and price.
- Does a bigger house always need more panels?
- Only if it uses more electricity. The tables are in kWh because that is the only figure the maths needs: a large, well-insulated house with gas heating can use less than a small one with electric heating and a pool pump. Ofgem's low band (1,600 kWh a year) needs 4 panels in London; the high band (3,800 kWh) needs 9.
- Will the panels cover the whole bill?
- Over the year, yes if sized to 100% and the roof faces south; over the day and the seasons, no. A grid-tied system exports in summer and at noon and buys in winter and at night, so the bill depends on what the utility pays for exports. The calculator has a coverage field if you want to size for a share of the use, and the 7.6 kW example above takes 414 sq ft (38.4 m²) of panel area before gaps and setbacks.
More guides
- How many solar panels for 2,000 kWh a month?
2,000 kWh a month is 65.8 kWh a day: 43 panels of 400 W (17.2 kW) at 4.5 sun hours, about $44,720 installed. Every US state and UK city.
- How many solar panels to produce 30 kWh per day?
20 panels of 400 W (7.75 kW) make 30 kWh a day at 4.5 peak sun hours; 25 at 3.5 hours, 16 at 5.5. 5 to 50 kWh a day, every US state and UK city.
- How many solar panels for 1,000 kWh a month?
1,000 kWh a month is 32.9 kWh a day: 8.5 kW of solar, 22 panels of 400 W, at 4.5 sun hours. Sizes at 3 to 6 sun hours, every US state and UK city.
- How many solar panels for 1,500 kWh a month?
1,500 kWh a month is 49.3 kWh a day: 12.7 kW of solar, 32 panels of 400 W, at 4.5 sun hours. Sizes at 3 to 6 sun hours, every US state and UK city.
Last updated 2026-10-03. Estimates from published averages (NREL, EIA, Ofgem, industry cost surveys), each with its source and date: an installer's site survey and shading analysis replace them. Not financial advice.