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 |
| Fresno, CA | 1,827 | 31.2¢ | 8.8 yrs |
| Chesapeake, VA | 1,604 | 14.2¢ | 10.4 yrs |
| Salt Lake City, UT | 1,659 | 11.2¢ | 13 yrs |
| Gatineau, QC | 1,291 | 7.9¢ | 33.3 yrs |
Frequently asked
Can solar panels run a house without batteries?
Yes, if you stay grid-connected. You export surplus during the day and draw from the grid at night. Without batteries you lose power during a grid outage.
How many solar panels to run an air conditioner?
A central AC unit uses roughly 3,000 kWh over a cooling season, needing about 5 to 7 panels to cover it.
How many kWh does a house use per day?
The US average is about 30 kWh a day, or 10,800 kWh a year. All-electric homes and homes with EVs use considerably more.
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General information, updated 2026-08-22. Not financial, tax or engineering advice.