Home Battery Storage Calculator 2026: Cost & Payback
Size a home battery for backup and estimate 2026 installed cost, rebates, savings and payback. No federal tax credit applies to batteries installed in 2026.
Estimate scope & data quality
This tool provides an input-driven estimate. Use the required inputs shown above and review the result limitations below.
- Data quality
- NOT_AVAILABLE
- Result limitation
- Calculator output is not a source-complete customer result.
A tariff credit is distinct from annual savings. If a result is NOT_COMPUTABLE or CONFLICT, it must not be replaced with an estimate or treated as canonical.
How to use this calculator
- Enter your average daily electricity usage in kWh (divide the monthly kWh on your utility bill by 30).
- Enter how many days of backup power you want during an outage.
- Adjust the depth of discharge — how much of the battery you're willing to use (80% is standard).
- Enter your electricity rate, the installed cost per 13.5 kWh battery and any state or utility rebate you have confirmed.
- Results show the capacity you need, the number of 13.5 kWh units, installed cost, net cost after rebates, annual savings and payback.
Understanding your results
Capacity needed = daily usage × days of backup ÷ depth of discharge. At the defaults (30 kWh/day, 1 day, 80%) that is 30 × 1 ÷ 0.80 = 37.5 kWh, or three 13.5 kWh units.
Installed cost = units × installed price per unit. The default of $13,500 per 13.5 kWh unit sits in the typical 2026 range of roughly $12,000–$16,000 installed (LBNL Tracking the Sun and EnergySage report prices; your quotes will vary). Net cost after rebates subtracts only the rebate you enter — there is no federal credit for homeowner-owned batteries installed in 2026.
Annual savings assumes about 40% of your daily usage is shifted from grid power to stored power at your electricity rate: 30 kWh × $0.182 (US average, EIA, July 2026 year-to-date) × 365 × 0.40 ≈ $797/yr at the defaults. Real savings depend heavily on your rate plan — time-of-use rates, net billing or CA NEM 3.0 (where exported solar earns little) and utility demand-response programs raise the value; flat rates with full retail net metering lower it.
2026 federal policy. Until Dec 31, 2025, homeowners could claim 30% of battery costs (3 kWh+) under §25D; the One Big Beautiful Bill Act (Public Law 119-21, signed July 4, 2025) ended it for expenditures made after that date, and the IRS treats the expenditure as made when installation is complete (see the IRS OBBB FAQs). Batteries installed in 2025 are claimed on the 2025 return. A leased or third-party-owned battery may still be priced with the business credit (§48E) through 2027. This is not tax advice; confirm with a tax professional.
Payback reality. A battery sized for a full day of whole-home backup (three units, $40,500 at the defaults) will not pay back on bill savings alone (≈51 years). One unit ($13,500) at the same $797/yr takes about 17 years. Most households buy batteries for backup first and treat savings as a partial offset.
Frequently asked questions
Direct answers for US homeowners.
Related guides
In-depth articles on sizing, costs, and energy decisions.