There's no single right answer for backup power — the right choice depends on outage frequency, budget, and how much of the house you actually need to keep running.
Gas generators: cheapest upfront, costs accumulate with use
A gas or propane generator has the lowest purchase price of the three options and can run indefinitely as long as fuel is available — but every hour of use adds fuel cost, and larger units require enough surge capacity for whatever motor-driven appliances (well pump, AC, fridge) need to start. Check your actual fuel burn with the fuel consumption calculator before assuming a tank lasts as long as you'd hope.
Home batteries: highest upfront cost, near-zero marginal cost
A home battery system costs considerably more to install than a generator, but has almost no cost per outage — it's already charged and switches over automatically with no fumes, noise, or manual startup. It also does double duty for time-of-use savings or solar storage even when there's no outage at all, which a generator can't do. Compare the real 10-year numbers with the home battery vs generator calculator using your actual outage frequency.
Portable solar generators: best for light loads over multiple days
A portable solar power station sits in between — cheaper than a home battery system, no recurring fuel cost like a gas generator, but limited by its own battery capacity and how much sun is available to recharge it. It's a strong fit for essentials (lights, phones, a CPAP, a small fridge) during a multi-day outage, but isn't sized for whole-home loads like a gas generator or full battery system can be. See the direct comparison in the solar generator vs gas generator calculator.
The variable that decides it: outage frequency
Frequent, short outages tend to favor batteries — the upfront cost gets used often enough to justify itself, and there's no fuel logistics to manage. Rare, occasional outages tend to favor a generator, since a battery sitting mostly idle is a lot of upfront cost for infrequent use. Run your own outage pattern through the comparison calculators above rather than assuming one option is universally "better."
Frequently asked questions
Which backup option is quietest?
A home battery system and a solar power station are both silent, with no moving parts or combustion — a gas or propane generator is the only option of the three that produces noise and exhaust fumes.
Can a portable solar generator run a whole house?
Generally no — portable solar power stations are sized for essential loads like lighting, phone charging, and a small fridge, not whole-home demand, which typically needs either a much larger battery system or a generator.