- Independent site. We do not sell or install batteries.
- Planning estimate only. Not a quote, not tax advice, not installation advice.
- US homeowners. State programmes and utility rules decide the numbers, not national averages.
- No sign-up. No account, no lead form to use a calculator.
- Maths in your browser. No calculator input is sent anywhere.
Start here
Two calculators, in the right order
Home Battery Size Calculator
Answers one question: how many kWh do you need, and how many 13.5 kWh example units does that mean? Daily use × outage hours ÷ 24, rounded up to whole units.
Home Battery Cost & Payback Calculator 2026
Answers the next question: installed cost, $0 federal credit, bill savings plus any confirmed programme payment — and the simple payback that follows from those numbers, not from a promise.
Build Your Backup Load
Drag your appliances — fridge, TV, lights, fans, iron — into My Home and see the watts, the battery size, and the cost range live. Fun to play with, free, no sign-up.
Both calculators show their formulas on the page. Get a site-specific quote from a licensed installer, check your utility's rules, and speak to a tax professional before buying.
How it works
Three steps, then you talk to an installer
Size it
Whole home or essential loads only? Your daily use and the outage hours you want to cover decide the answer — not a brand, and not a neighbour's system.
Price it in 2026
Use the post-credit maths. No 30% credit for a homeowner-owned 2026 install, and no programme payment unless your own utility confirms one.
Check your state
Programmes, export rates, and outage patterns are state-specific. Check the official page for your utility and address before you sign anything.
By state
State pages first — national averages do not decide a battery
Massachusetts
ConnectedSolutions demand-response example, plus what to check officially.
Rhode Island & Connecticut
Blog guide, programme TODO — not filled with a copied rate.
Guides & blog
Read one guide before you buy
Guides: whole-home vs essential loads, buy vs lease in 2026, and 7 mistakes. Blog: state guides, payback, panel upgrades, solar + battery vs battery alone, EV owners, warranties, and multi-day outage planning.
Our editorial line, plainly stated: judge a battery on backup first, not on an ROI promise. If the backup case does not work for your home, a payback spreadsheet should not talk you into it.
Figures used
Research examples only — not your home's numbers
Figures used on this site come only from the research reports, with sources labelled: installed cost roughly $12,000–$16,000 per 13.5 kWh unit in 2026 (GreenEnergyCalc / NuWatt, via the research reports); bill-shifting example ~$797/year at the research calculator's defaults for one unit (~17 years at those defaults; 15.1–20.1 years across the ends of the cost range); MA/RI/CT ConnectedSolutions demand-response example about $1,125–$1,375/year (~6–8 years at those defaults; 5.5–8.3 years across the ends of both ranges). Those examples are not your home's saving or your utility's rate.
What this site will not do
- No guaranteed saving, discount, or payback figure as a benefit of using a link.
- No state rate copied from another state, blog, or directory.
- No live affiliate link yet — see Affiliate Disclosure for exactly what is and is not live.
Frequently asked questions
Is a home battery worth it in 2026 now that the federal credit is gone?
It depends on your state programme, your outage risk, and your peak rates — not on a national average. Use the size calculator, then the cost calculator with a programme payment only if your official utility programme states one. On bill savings alone, the research examples show a long payback; backup and programme payments are the main value, not a guaranteed investment return.
Do I need solar to get a home battery?
No. A battery can charge from the grid. Solar changes the maths (recharging during an outage, export rates), but battery-only is a real option — check your utility's battery rules and any advisor route for battery-only quotes, and do not assume a solar+battery quote funnel covers battery-only.
What should I check before buying?
Your licensed installer's site-specific quote, your utility's programme terms and export rate for your exact address, your panel capacity, and the battery warranty terms (cycles, throughput, degradation) on the manufacturer's spec sheet.
Next steps: Battery size calculator · Cost & payback calculator · State pages · Guides · Blog