Solar + battery vs generator: backup math
Decisions built from Solar + battery and Whole-home generator — editorial analysis, no sales stake; each figure sourced or labeled in review.
The generator answers one question ('will my lights turn on tonight?') and solar-plus-battery answers four more every day. As backup power, they differ in fuel, noise and maintenance; as an investment they are not the same thing at all.
At a glance: Solar + battery vs Whole-home generator
| Solar + battery | Whole-home generator | |
|---|---|---|
| Fuel | Sun — no tank to fill | Gas/propane, refills |
| Noise | Silent | Loud during outages |
| Outage cap | Till the battery is empty | While fuel lasts |
| Daily value | Bills & export credits every day | Nothing on a normal day |
When Solar + battery wins
- Short outages, and you want your panel bill and resilience solved by one system.
- Net-credit state-case value: battery shifts evening consumption off-peak, earning the difference.
When Whole-home generator wins
- Long multi-day outages (hurricane weeks) where a battery covers hours, not days.
- House loads beyond the battery (furnace blowers) need headroom — a generator is built for that.
The honest verdict
Go battery+solar if your outages are a few hours to two days and you're already solar; go generator if your feeder is genuinely days-long and repeated. 'Sub-solar' sizing is the middle: a battery chosen for evening shift, plus a $500 portable generator for multi-day backstop.
Where these figures come from
Federal credit rules from the IRS (accessed 2026-08-08); market prices from EnergySage 2026; export rates per state records cited on each state page (CPUC NEM 3 for California); typical-home usage EIA 2023. Anything verified carries its date; the rest says "in review" until confirmed.