Are solar batteries worth it?
For most homes on classic net metering, a battery lengthens payback rather than shortening it. It costs $8,000–15,000 and saves money only on the gap between import and export prices. Where it does pay is poor export rates, frequent outages, or wide time-of-use spreads.
What a battery actually does financially
A battery stores midday surplus so you use it in the evening instead of exporting it. Its value is therefore the difference between what you would pay to import that power and what you would have been paid to export it.
| Your situation | Value of stored kWh | Verdict |
|---|---|---|
| Classic 1:1 net metering | ≈ $0 | The grid already banks your power at full value. A battery adds backup, not savings. |
| Net billing (e.g. California) | ~20–35¢ | Real savings. Increasingly what makes solar work there at all. |
| Wide time-of-use spread | 10–25¢ | Worth modelling. Charge cheap, discharge at peak. |
The rough arithmetic
A 13.5 kWh battery cycled once daily moves about 4,000 kWh a year. At a 25¢ spread that is $1,000 a year against a $12,000 cost — roughly a 12-year payback on a unit typically warranted for 10 years. At a 5¢ spread it is $200 a year, which never pays back.
Reasons to buy one anyway
- Outages. Grid-tied solar without a battery shuts off during a blackout for lineworker safety. If you lose power often, backup has real value that has nothing to do with payback.
- Medical or work-critical equipment. Hard to price, easy to justify.
- Incentives. Batteries of 3 kWh and up qualify for the 30% federal credit, and some states add storage rebates.
Sizing
Most homes land on 10–15 kWh. That covers an evening and overnight for normal loads. Whole-home backup including air conditioning or electric heat needs considerably more, plus an inverter rated for the surge.
Check your export rate first → It decides this question more than anything else.
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 |
|---|---|---|---|
| Kahului, HI | 1,627 | 42.1¢ | 3.5 yrs |
| Silver Spring, MD | 1,481 | 18.3¢ | 8.8 yrs |
| Woodbury, MN | 1,483 | 14.8¢ | 10.9 yrs |
| Slough, South East | 1,006 | 26.1¢ | 12.9 yrs |
| Trois-Rivières, QC | 1,347 | 7.9¢ | 31.9 yrs |
Frequently asked
How long do solar batteries last?
Most home batteries are warranted for ten years or a set number of cycles, whichever comes first — shorter than the panels they support. Expect to replace the battery at least once during the system's life, and include that cost when comparing a battery system against panels alone.
Can a battery take me off-grid?
Not realistically for most homes. Going fully off-grid requires enough storage to cover consecutive dark days plus a much larger array, which costs far more than staying connected. A typical home battery is sized for evening use and outage backup, not for weeks of winter independence.
Does a battery qualify for the tax credit?
Standalone home batteries above a minimum capacity generally qualify for the US federal credit, whether or not they are installed alongside solar. The requirements have changed in recent years, so confirm current rules and capacity thresholds with a tax professional before counting the credit in your numbers.
Related guides
General information, updated 2026-08-22. Not financial, tax or engineering advice.