How Long Will a Tesla Powerwall Power a House?
Short answer: about 11 hours for an average U.S. home, on one Powerwall 3 with no solar. Here is the math, so you can swap in your own bill.
Worked example
- Powerwall 3 stores 13.5 kWh (Tesla datasheet; rated at 77°F, beginning of life).
- The average U.S. home bought 863 kWh a month in 2024 (EIA, Table 5A, latest release, checked Oct 23, 2026). 863 × 12 = 10,356 kWh a year, ÷ 8,760 hours = about 1.18 kWh per hour.
- 13.5 ÷ 1.18 = about 11.4 hours.
| Scenario | Avg use per hour | Math | 1 Powerwall 3 (13.5 kWh) | 2 Powerwall 3 (27 kWh) |
|---|---|---|---|---|
| U.S. average home (863 kWh/mo) | 1.18 kWh | 13.5 ÷ 1.18 | ~11.4 h | ~22.8 h |
| Texas average home (1,096 kWh/mo) | 1.50 kWh | 13.5 ÷ 1.50 | ~9.0 h | ~18.0 h |
| Essentials only (example: half the U.S. average) | 0.59 kWh | 13.5 ÷ 0.59 | ~22.8 h | ~45.7 h |
| Average home plus a 3-ton AC running nonstop | 4.18–4.68 kWh | 13.5 ÷ (1.18 + 3.0 to 3.5) | ~2.9–3.2 h | ~5.8–6.5 h |
Usage: EIA 2024 Table 5A. 3-ton AC running watts (3,000–3,500 W): Champion wattage chart. The essentials row is an example, not a measurement, and the AC row is a worst case, since real compressors cycle. Checked Oct 23, 2026.
Work out your own number in 3 steps
- Find your monthly kWh on your bill.
- Divide by the days in the billing period, then by 24. That is your average kWh per hour.
- Divide 13.5 (one Powerwall 3) by that number. The answer is hours of backup at your average use.
Example: 900 kWh over 30 days is 30 kWh a day, or 1.25 kWh an hour. 13.5 ÷ 1.25 = 10.8 hours. Turn off the dryer and that number goes up; plug in the EV and watch it fall.
How solar stretches it
Powerwall 3 has a built-in solar inverter that takes up to 20 kW DC of panels, and it can charge at up to 5 kW (datasheet). On a sunny day during an outage, panels can refill the battery while you run lighter loads, so backup can last well past the no-solar figure above. How far depends on your array, the weather and the time of year.
Powerwall 3 at a glance
- 13.5 kWh energy, 11.5 kW continuous power, starts loads up to 185 LRA.
- Built-in solar inverter, up to 20 kW DC of solar; up to 5 kW charging.
- Up to 4 units can be linked; 10-year warranty; 287 lb.
All from Tesla’s Powerwall 3 datasheet. Running the AC? See can a Powerwall run an air conditioner.
Backup hours vs. battery lifespan
This page is about hours in an outage. For years, warranty and how much capacity Tesla promises at year 10, see how many years a Tesla Powerwall lasts.
FAQ
How long will a Powerwall 3 last in an outage?
At average U.S. use, about 11 hours on one unit with no solar. With solar recharging by day and lighter use at night, it can go much longer. Heavy loads cut it fast.
How do I work out my own number?
Take your monthly kWh from your bill, divide by the days in the bill and by 24 to get kWh per hour, then divide 13.5 by that.
Does solar make it last longer?
Yes. Powerwall 3 takes up to 20 kW DC of solar directly and charges at up to 5 kW, so sunny days refill it. How much depends on your array and the weather.
Can I stack more Powerwalls?
Yes. The datasheet lists up to 4 Powerwall 3 units in one system. Two units double the 13.5 kWh to 27 kWh.
How long will a Powerwall run a fridge?
Find the kWh per year on the fridge’s yellow EnergyGuide label, divide by 365 for kWh per day, then divide 13.5 by that for days. For the portable-battery version, see how long a solar generator will run a fridge.
What is a Tesla Powerwall?
A Powerwall is an energy storage device that captures sunlight and converts it to electricity you can use for home use. It stores this stored power for later use or provides backup energy during grid outages.
How Long Will a Powerwall Power a House?
How long your house can run off-grid by using the Powerwall depends on several factors, such as how much electricity you use and whether or not it’s off-grid. Pair it with solar panels and sunny days can recharge it without the grid (see “How solar stretches it” above).
One Powerwall stores 13.5 kWh. How long that lasts depends on what you run; see the worked example above.
The Powerwall is an attractive option for those seeking energy independence, reduced bills, or minimal environmental impact. But it may not be suitable for everyone; there are other available solutions as well.
What is the Cost of a Powerwall?
The price of a Powerwall depends on several factors, including its size and type of energy consumed. It may also differ by region and battery manufacturer so be sure to research prices in your area before making a final decision.