Solar Batteries 101: How Home Storage Works & When It Pays
What a home battery does, how much it costs, and when it actually pays off — the basics every solar shopper should know before adding storage.
By The PVFig Editorial Team · 2026-08-10 · reviewed against EIA, NREL and DSIRE sources
What a battery does
A home battery stores surplus solar power during the day and discharges it at night or during outages. It shifts your self-consumption from ~30% to ~70–90%, which matters enormously in net-billing states where exports pay little.
Cost and sizes
A 13.5 kWh battery (like Powerwall 3) costs roughly $10,000–$15,000 installed before incentives. Typical homes need 1–2 batteries. Battery capacity is the main driver of cost — don't buy more than your critical loads need.
When it pays vs when it's backup only
In net-billing states (CA, NV, AZ, HI), batteries pay for themselves in 6–9 years via arbitrage. In full-retail 1:1 states, the spread is near zero — batteries are for blackout backup, not savings. Use the PVFig battery calculator for your state.
FAQ
How much does a home solar battery cost?
About $10,000–$15,000 installed for a 13.5 kWh battery before incentives. Larger systems scale up from there.
Do I need a battery with solar?
Only in net-billing states (CA, NV, AZ, HI) or if you want outage backup. With full-retail net metering, a battery rarely pays for itself on economics alone.
How long does a solar battery last?
Most lithium-ion home batteries carry 10-year warranties covering ~70% capacity retention, typically lasting 10–15 years in practice.
Ready to compare real installer quotes?
The estimates above are based on public data — your actual price depends on your roof, installer, and market. EnergySage collects quotes from pre-screened installers in one place (free, no obligation).
Compare quotes on EnergySage →
We may earn a commission if you sign up through links above — it never affects our data or estimates.
Sources
- U.S. EIA — electricity rates by state, eia.gov/electricity/monthly
- NREL PVWatts v8 — solar production by location, pvwatts.nrel.gov
- DSIRE — state incentives and net metering, dsireusa.org
- See how every figure on this page is calculated — PVFig methodology.
Comments powered by GitHub Discussions — enable by configuring the Giscus repo in
app/components/Comments.tsx.