How many solar panels does it take to run a whole house?
About 15 to 22 panels — roughly a 6 to 9 kW system — covers an average home's 10,800 kWh a year while staying grid-connected. Running genuinely off-grid needs closer to double that, plus a large battery bank, because you must survive your worst week rather than average across the year.
Grid-tied vs off-grid: very different numbers
| Grid-tied | Off-grid | |
|---|---|---|
| Sized against | Annual total | Worst month |
| Panels for average home | 15–22 | 30–45 |
| Battery | Optional | Essential, 20–40 kWh |
| Typical cost | $22,800 | $68,400+ |
The gap exists because the grid acts as a free, infinitely large battery. Off-grid, you carry that storage yourself and must oversize for December.
What uses the power
| Load | kWh/year | Panels to cover it |
|---|---|---|
| Heat pump (heating + cooling) | 6,000 | 12 |
| Electric water heater | 3,500 | 7 |
| EV, 15k km/yr | 3,000 | 6 |
| Fridge + freezer | 900 | 2 |
| Lighting | 600 | 2 |
| Laundry | 700 | 2 |
| Cooking (electric) | 800 | 2 |
Panel counts assume 1,545 sun hours a year. Sunnier locations need fewer.
Add an EV and the maths changes
An electric car is often the single largest load a home adds, and it roughly doubles many households' electricity use. If an EV is on the horizon, size for it now — adding panels later means a second permit, a second crew visit, and possibly an inverter that's already maxed out.
Check how many panels your roof can actually hold →
What this looks like in real cities
Measured rooftop data, spanning the range from fastest to slowest payback we have found:
| City | Sun hrs/yr | Rate | Payback |
|---|---|---|---|
| Honolulu, HI | 1,787 | 42.1¢ | 3.1 yrs |
| Oakland, CA | 1,793 | 31.2¢ | 8.8 yrs |
| Roswell, GA | 1,584 | 14.1¢ | 10.9 yrs |
| Basingstoke, South East | 1,014 | 26.1¢ | 12.9 yrs |
| Gatineau, QC | 1,291 | 7.9¢ | 33.3 yrs |
Frequently asked
Can solar panels run a house without batteries?
Yes, and most systems do. During daylight your home draws from the panels first and the grid makes up the rest; at night you buy from the grid as normal. Without a battery you also lose power during an outage, because grid-tied systems shut down for line-worker safety.
How many solar panels to run an air conditioner?
A typical central air conditioning unit draws 3 to 5 kW while running, so roughly 8 to 13 panels' worth of instantaneous output. Cooling demand peaks in the afternoon when solar output is still strong, which is why solar pairs unusually well with air conditioning in hot climates.
How many kWh does a house use per day?
The average US home uses about 10,800 kWh a year, or roughly 30 kWh a day. Yours may differ substantially — electric heating, an EV or a pool can double it, while a small gas-heated home may use half. Your own bills are the only reliable source for this.
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General information, updated 2026-08-22. Not financial, tax or engineering advice.