Short answer: a home battery is worth it mainly for backup power during outages. As a pure money-saver it usually pays back slowly: a typical Powerwall 3 installs for about $13,500 and saves roughly $500 to $900 a year in most places, a payback of 15 years or more.
What a home battery costs
The Tesla Powerwall 3 stores 13.5 kWh and delivers 11.5 kW. EnergySage puts the typical all-in installed cost before incentives at about $13,500, or roughly $1,000 per kWh of storage. Other brands are in a similar range per kWh. The federal 30% credit for residential storage ended with the other residential energy credits on December 31, 2025, so check irs.gov and your state or utility for rebates (some states pay for batteries that support the grid).
Where the value comes from
- Backup power: keeps the fridge, lights, internet and medical devices running in an outage. Hard to price, but decisive if outages are frequent.
- Time-of-use savings: store cheap power (or solar) and use it when rates peak.
- Solar self-consumption: where your utility pays little for exported power, storing midday solar for the evening is worth more.
- Utility programs: some pay you to let the battery support the grid on hot days.
A payback example
Assume 12 kWh of usable energy shifted each day (13.5 kWh at about 90% round-trip efficiency).
| Price gap between peak and off-peak | Daily saving | Yearly saving | Payback on $13,500 |
|---|---|---|---|
| 10 cents/kWh | $1.20 | about $440 | about 31 years |
| 20 cents/kWh | $2.40 | about $880 | about 15 years |
| 30 cents/kWh | $3.60 | about $1,310 | about 10 years |
Batteries typically carry 10-year warranties, so payback beyond that is a gamble. Only a large price gap, or a high value on backup, makes the numbers work.
Who should buy one
- You live where outages are frequent or long (storm, wildfire or heat-wave areas).
- Your utility has steep time-of-use rates or pays little for solar exports.
- Someone at home relies on electrically powered medical equipment.
- You already have, or are installing, solar.
Who should skip it
If your power rarely goes out and you have flat rates, a battery is mostly an expensive insurance policy. A smaller option such as a portable power station may cover your needs for a fraction of the price.
FAQ
How long does a home battery last? Expect 10 to 15 years of useful life; warranties usually guarantee a set capacity (often 70%) at 10 years.
Can a battery run my whole house? It depends on loads. One battery can run essentials for a day or more but not central air conditioning for long.
Can I add a battery later? Often yes, if your solar inverter is compatible. Ask your installer.
Estimates only; get quotes. This is general information, not financial advice.