Best Whole-House Standby Generators
Whole-house coverage means nobody flips breakers when the power fails: the automatic transfer switch carries every circuit, including central air. That takes roughly 15 kW and up for a typical home, with 22–26 kW the mainstream choice. All of these are permanently installed natural-gas or propane units; a licensed electrician must run a load calculation on your actual panel before any of these numbers are more than a starting point.
Sizing target: a running rating of at least 15,000 W (15 kW+) on its best fuel. Filtered to home standby units rated 15,000+ running watts, ordered by output on their best fuel. Rankings use published specifications only — no prices or sponsorships.
| Model | Running W (best fuel) | Starting W | Noise | Est. runtime @ 25% | Est. fuel cost/day |
|---|---|---|---|---|---|
| Cummins QuietConnect RS30 30kW Liquid-Cooled | 30,000 | — | 60 dBA | — | $79 (natural gas) |
| Briggs & Stratton PowerProtect DX 26kW (040806) | 26,000 | — | 65 dBA | — | $74 (natural gas) |
| Generac Guardian 26kW (7290) | 26,000 | — | 67 dBA | — | $67 (natural gas) |
| Generac Guardian 26kW with 200A ATS (7291) | 26,000 | — | 67 dBA | — | $67 (natural gas) |
| Kohler 26RCA 26kW | 26,000 | — | 67 dBA | — | $65 (natural gas) |
| Kohler 26RCAL 26kW with ATS | 26,000 | — | 67 dBA | — | $65 (natural gas) |
| Cummins QuietConnect RS25 25kW Liquid-Cooled | 25,000 | — | 64 dBA | — | $67 (natural gas) |
| Generac Guardian 24kW (7209) | 24,000 | — | 67 dBA | — | $73 (natural gas) |
| Generac Guardian 24kW with 200A ATS (7210) | 24,000 | — | 67 dBA | — | $73 (natural gas) |
| Kohler 24RCLA 24kW Liquid-Cooled | 24,000 | — | 61 dBA | — | — |
Runtime at 25% load and daily fuel cost are estimates derived from published spec-sheet figures — the formulas and their limits are on the methodology page. A dash means the manufacturer doesn't publish the underlying number.
Not sure this is your use case? Add up your actual loads with the generator sizing calculator, or start from the sizing guide.
Frequently asked questions
What does this list require of a generator?
Every model shown meets the sizing target: a running rating of at least 15,000 W (15 kW+) on its best fuel. Filtered to home standby units rated 15,000+ running watts, ordered by output on their best fuel.
How are these recommendations ranked?
Purely from published manufacturer specifications in the BackupAtlas dataset — no prices, sponsorships, or review scores are involved. Models missing the data a criterion needs are excluded rather than guessed at.
Are the wattage figures guaranteed?
They are the manufacturers' published ratings, and dual-fuel/natural-gas ratings differ by fuel — always size against the rating for the fuel you will actually run, and treat runtime and cost estimates as planning figures, not promises.