Calculators / Solar battery calculator
Is a battery worth it with my solar?
A battery changes one thing in the model: how much of your own production you use instead of exporting. Whether that is worth paying for depends almost entirely on your export rule.
A battery is a bet on your export rule
This is the whole of it, and it is worth stating plainly because most battery marketing avoids it. A battery lets you use electricity you generated earlier instead of buying it back. The value of doing that is the gap between what you pay for a kilowatt-hour and what you are credited for exporting one.
Where that gap is zero — full net metering — the battery has almost nothing to earn on this model, however good the hardware is. Where the gap is wide, as under an export rate set at a fraction of retail, the same battery earns on every kilowatt-hour it holds back. The export ratio used above is listed under the results with the tariff or commission order it came from, so you can check which case you are in before you read any conclusion.
Reading the comparison
Both columns are the same house, the same system and the same year, run twice through the same engine. The only input that differs is whether storage is present. The row that explains every other row is self-consumption; the row that decides the verdict is the 25-year net, because the battery has to earn back its own installed price before it adds anything at all.
Note what a battery does to payback even when it helps: it adds cost on day one and repays gradually, so the crossing point usually moves later even in the states where the 25-year figure improves. Both effects are real and the table shows both rather than choosing the flattering one.
What is not priced here
- Backup power. Not modelled. Worth a great deal to some households and nothing to others.
- Time-of-use arbitrage. Not modelled, because the engine uses an average annual rate. This understates a battery in states with steep peak pricing.
- Battery degradation and replacement. The comparison runs the full analysis period on the installed cost listed above. A battery that needs replacing inside that period would make the modelled case worse.
- Utility programmes that pay for discharge. Several states run them, they can be worth several hundred dollars a year, and they are not in this model.
Where storage pays, state by state
Is a home battery worth it in 2026? runs this comparison across every state we publish, sorted by what storage adds. The pattern it shows is the one this page predicts: the states where a battery earns are the states that took net metering away.
Questions
- What does a battery actually change in the model?
- One number: the share of your own generation you consume instead of exporting. Without storage a typical household uses about 40% of what the panels make as they make it; with a battery that rises to roughly 75%. Everything else in the comparison follows from that single shift, and both values are listed under the results.
- Why does a battery add so little in some states?
- Because under full net metering an exported kilowatt-hour is already worth a kilowatt-hour taken back later. The grid is doing for free what the battery would be paid to do, so storing the electricity yourself saves almost nothing. Batteries earn their price where exports are credited well below retail, which is exactly where net metering has been replaced.
- Does this include the backup value?
- No, and that is the honest limit of the comparison. This model prices only the electricity a battery shifts. If you lose power several times a year, a battery may be worth buying at a negative modelled return; that is a judgement about what an outage costs you, and only you can make it. Note also that solar without storage does not keep the lights on in a blackout.
- Why do the numbers here differ from an installer quote?
- Usually because of time-of-use rates. Where the price of electricity varies through the day, a battery can also arbitrage — charge cheap, discharge expensive — and a quote will often include that. This model uses a flat average rate, so it captures the self-consumption benefit and not the arbitrage one. That makes it conservative in states with steep time-of-use spreads.
The other calculators
All of them run the same engine on the same data, so two can never disagree. They differ in what they put first.
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A screening estimate from published data, not a quote and not tax or financial advice. Every input is listed under the results with the source it came from and the date it was read; the formulas are on the methodology page. Confirm against real quotes, and with a professional, before relying on any figure here.
Published 6 September 2026. Data last verified 6 September 2026. Rates: EIA 2026-07. Found a figure that looks wrong? Tell us — we publish corrections.