Can a battery back up your whole home?
It can, but "whole home" means two things: enough power to start the AC and water heater, and enough stored energy to last. Most homes need more than one unit, or a smaller list of what stays on.
We earn a commission if you buy through our links. It never changes our picks. Details
The short answer
One wired-in home battery stores about 5 to 15 kWh. The average US home uses about 30 kWh a day, so one unit runs the whole house for about 3 to 10 hours. To get through a day or more, most homes add units, back up only the essentials, or recharge from solar.
- 29.6
kWh a day for the average US home (10,791 kWh a year).
Source: EIA- 6,000 W
A 3-ton central AC running. A heat pump is about the same.
Source: DTE Energy- 4,500 W
An electric water heater while it heats.
Source: EWEB
What does “whole home” actually need?
Two numbers matter, and a battery has to meet both.
- Power, in kW. Everything that runs at once has to fit under the battery’s continuous rating. A 3-ton central AC alone is about 6,000 W, an electric water heater 4,500–5,000 W and an electric range with the oven on about 12,200 W (DTE Energy).
- Motor starts. AC compressors and well pumps pull a big burst to start. Home batteries list this as locked-rotor amps (LRA). Compare it with the LRA on your AC’s nameplate.
- Energy, in kWh. That’s how long it lasts. The average home’s 29.6 kWh a day (EIA) is more than any single unit below stores.
If you have central AC, electric heat, an electric water heater or a well pump, those decide the size. A home with gas heat and a gas water heater needs far less.
How do the whole-home batteries compare?
Specs per unit, from each maker’s data sheet. The last column is one unit running the average home with nothing turned off.
| Unit | Capacity | Continuous power | Motor start | Whole house, one unit |
|---|---|---|---|---|
| Tesla Powerwall 3 (wired) | 13,500 Wh | 11,500 W | 185 A LRA | 9 hrs |
| FranklinWH aPower 2 (wired) | 15,000 Wh | 10,000 W | 185 A LRA | 10 hrs |
| Enphase IQ Battery 5P (wired) | 5,000 Wh | 3,840 W | Up to 48 A LRA | 3 hrs |
| Anker SOLIX F3800 (portable) | 3,840 Wh | 6,000 W | 9,000 W surge | 3 hrs |
Manufacturer spec capacity, power and motor start · Our estimate runtime, using 85% of capacity and the average US home’s 29.6 kWh a day from EIA. How we calculate
Every one of these stacks. Tesla supports up to 4 Powerwall 3 units, and FranklinWH up to 15 aPower units per aGate. Three Powerwall 3s run the average home for about 28 hours, and three aPower 2s for about 31.
We list Powerwall 3 here for comparison. Ask an installer about it alongside the picks below.
Wired-in battery or a big portable with a transfer switch?
A wired-in battery sits on a wall or pad, connects at your panel, and switches over by itself when the grid drops. Tesla’s gateway, for example, detects the outage and moves the house to battery automatically (Tesla). It can back up the whole panel or a separate panel of essential circuits.
A big portable like the F3800 feeds chosen circuits through a manual transfer switch, or plugs into an inlet box outside with an interlock on the panel. You flip it over by hand. It costs less and moves with you, but it runs a handful of circuits, not the whole house.
Either way, the house has to be cut off from the grid while the battery feeds it. Feeding home wiring without a transfer switch can push power back onto the utility lines and endanger line workers and neighbors (Maryland Emergency Management / USFA).
Which setup fits your home
- Essentials only
- Fridge, lights, Wi-Fi, furnace fan and a few outlets. A big portable on a transfer switch, or one wired-in unit on an essentials panel.
- Most of the house, gas heat
- One or two 13–15 kWh wired-in units, sized so the continuous power covers your AC and the motor start covers its LRA.
- All-electric or a well
- Several units, plus rooftop solar to recharge by day. If that gets out of budget, compare it with a standby generator in battery vs. generator.
Do you need an electrician and a permit?
For anything wired in, yes. Home batteries connect at the electrical panel and go in under local electrical and fire codes. Enphase, for example, tells installers to follow the requirements of the local authority having jurisdiction (Enphase). An inlet box or transfer switch for a portable is also an electrician’s job in most places.
Plan for a site visit, a permit, and sometimes a utility sign-off if the battery connects to solar.
What does a whole-home battery cost installed?
Installed prices vary with the number of units, the panel work and your area. Get quotes from more than one certified installer, since the battery is only part of the cost. A large portable plus a transfer switch typically costs less; get an electrician’s quote for the switch.
Three ways to back up the house
Specs are the manufacturer's. Runtimes are our estimate for one unit running the average US home with nothing turned off.
Most power per unit of these picks
FranklinWH aPower 2
About 10 hrs per unit at the average US home's daily use Our estimate
15,000 Wh · 10,000 W (15,000 W surge) · LFP, cycles not published · 357 lb Manufacturer spec
15 kWh and 10 kW continuous per unit, with a 185 A motor-start rating, and it stacks up to 15 units. It's AC-coupled, so it can be added to an existing solar system.
Trade-off: At 357 lb it is an installer job, and FranklinWH publishes a throughput warranty (15 years or 60 MWh) rather than a cycle rating.
Best for adding storage in small steps
Enphase IQ Battery 5P
About 3 hrs per unit at the average US home's daily use Our estimate
5,000 Wh · 3,840 W (7,680 W surge) · LFP, 6,000-cycle warranty · 174 lb installed Manufacturer spec
5 kWh per unit, so you can start with one or two and add more. It works with Enphase IQ and M Series microinverters.
Trade-off: At 3.84 kW per unit, you need two or more to run a 3-ton central AC (about 6,000 W).
Best if you want to take it with you
Anker SOLIX F3800
About 3 hrs at the average US home's daily use Our estimate
3,840 Wh · 6,000 W (9,000 W surge) · LFP, 3,000+ cycles · 132 lb Manufacturer spec
A 3,840 Wh portable with 120/240 V output. With a transfer switch or Anker's home panel it runs chosen circuits, and it moves with you.
Trade-off: It runs selected circuits, not the whole house, and it is unlikely to start a 3-ton central AC.
Common questions
How long will a home battery run my whole house?
At the average US home's use of about 30 kWh a day, a 13.5 kWh battery runs everything for about 9 hours. Turning off heating, cooling and the water heater stretches it, and the runtime calculator shows by how much for your own list.
Can a home battery run central air conditioning?
Some can. A 3-ton central AC draws about 6,000 W running, so the battery needs that much continuous power plus a motor-start rating above the AC's locked-rotor amps (LRA). Tesla and FranklinWH both list 185 A LRA; check your AC's nameplate.
Do I need a permit for a home battery?
Usually, yes. A wired-in battery connects to your electrical panel, so it goes in under your local electrical code, installed by a licensed electrician or certified installer. Ask your installer who handles the permit.
Can I use a portable power station instead of a home battery?
For chosen circuits, yes, through a transfer switch or inlet that an electrician installs. Never plug a battery or generator into a wall outlet to feed the house; that can energize the utility lines outside.
