Generators are sold on peak watts and brand hype. What matters is running watts, the power it actually supplies, and how much of it you get for your money. This ranks every popular model by cost per 100 running watts. Filter by inverter or conventional, since they are different tools, then size it to what you need to power.
Prices reviewed 11 July 2026. Generator prices spike around storm season, so check the live listing.
| Generator | Running W | Peak W | Fuel | Type | Price | $/100W |
|---|
Add the running watts of what you power at once. Fridge, lights and phones: ~2,000. Add a window AC or sump pump: 3,500-5,000. Most of a house: 7,500-10,000. Size by running watts and leave headroom.
Running (rated) watts is continuous power and the number to size by. Starting (peak/surge) watts is a brief burst for motors kicking on. We rank by cost per running watt, the honest continuous capacity.
Inverter: cleaner, quieter, fuel-sipping, electronics-safe, but pricier per watt. Conventional: far more watts per dollar for tools and rough backup. Compare within one type.
For backup, usually. Propane stores for years unlike petrol, so dual-fuel is more reliable for unpredictable emergencies, for a small price premium.