Solar Battery Storage ROI Calculator
The federal 25D credit ended for systems installed after 2025; check state and utility rebates
What the battery can replace during peak hours
Off-peak grid price, or the export credit you give up by storing your own solar
About 85–92% for lithium batteries
Warranties often guarantee 70% after 10 years
Payback
10.0 years
- First-year savings
- $1,046
- Savings over 12 years
- $14,850
- Net after cost
- $2,850
- Saving per kWh shifted
- $0.287
Each kWh used at peak saves $42 per 100 kWh but costs $13 per 100 kWh to store after 10% round-trip losses.
Cumulative net savings
Years on the horizontal axis; the line crosses zero at payback.
Counts time-of-use savings only. Backup power during outages, demand charges, virtual power plant payments and replacement of an inverter are not valued. Capacity fades each year and electricity prices rise at the rate you set.
Estimate the payback of a home battery used for time-of-use savings: the saving on each kilowatt-hour moved from peak to off-peak after round-trip losses, first-year and lifetime savings with capacity fade and rising prices, and the payback year.
Formula
Worked Example
Each kWh used at peak avoids $0.42 but costs $0.12 ÷ 0.9 = $0.133 to store, so it saves $0.287. Ten kWh a day for a year saves $1,046, and with rising prices offsetting capacity fade the battery pays for itself in about ten years.
Frequently Asked Questions
Is a home battery worth it financially?
Mostly where there is a large gap between peak and off-peak prices, low export credits for solar (as under California's net billing), or payments for joining a virtual power plant. With flat rates and full net metering, a battery rarely pays back on savings alone and is bought mainly for backup power.
Is there still a tax credit for home batteries?
The federal 25D residential clean energy credit, which covered 30% of battery and solar costs, ended for systems installed after December 31, 2025. Some states and utilities still offer rebates, and leased systems may be priced with the commercial credit.
How long do home batteries last?
Lithium iron phosphate home batteries typically carry 10-year warranties that guarantee about 70% of the original capacity, with a cap on total throughput. Losing 2–3% of capacity a year is a common planning assumption.