In this section
- CalculatorSizing calculatorWhat size generator do you need? Tick what must run at once and get running watts, starting watts and the size to shop for.
- GuideSafety rulesThe rules that keep generator users alive: where to put it, carbon monoxide alarms, extension cords, refueling, and why you never plug a generator into a wall outlet.
Carbon monoxide kills. Run a generator only outdoors, more than 20 feet from doors, windows and vents, with the exhaust pointed away from the house. Never in a garage, basement, porch or shed, even with the door open. Put battery carbon monoxide alarms on every floor. (CDC, CPSC)
Inverter or conventional?
- Inverter generators make clean, stable power that’s safe for electronics, throttle down when the load is light, and are much quieter. Most are under 4,500 W.
- Conventional (open-frame) generators are cheaper per watt and come in larger sizes, but they’re loud and run at full speed regardless of load.
Fuel
- Gasoline is everywhere but goes stale in months; add stabilizer and run the generator monthly.
- Propane stores indefinitely in tanks, which suits a generator that sits most of the year. Output is lower on propane.
- Dual fuel models run on either. For backup use, we think it’s worth paying for.
CO shutoff is now standard
Look for a carbon monoxide shutoff feature, sold under names like CO-MINDER (Honda), CO Shield (Champion), COsense (Generac) and CO sensor (Westinghouse). It shuts the engine down if CO builds up around it. It doesn’t make indoor use safe.
Size it
Add up the running watts of everything that must run at once, then add the biggest starting surge of any motor in the list. Use the sizing calculator.
Running a hard-wired furnace, well pump or sump pump on a dedicated circuit means connecting to your home’s wiring, which needs a transfer switch or interlock installed by a licensed electrician. How whole-home backup works.
Picks
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Honda EU2200i
Quiet, clean power for a fridge and essentials
- 2,200 W starting, 1,800 W running
- Inverter, so safe for electronics
- CO-MINDER shuts it off if carbon monoxide builds up
Known for long life and quiet running; a good fridge-and-lights generator.
Watch for: Too small for a well pump or central AC.
Champion 2500-Watt Dual Fuel Inverter
Small inverter that also runs on propane
- Gasoline or propane
- Inverter output
- CO Shield automatic shutoff
Propane stores for years, which matters for a generator that sits most of the year.
Watch for: Running watts are lower on propane than on gasoline.
Westinghouse iGen4500
Fridge, freezer, sump pump and a window AC
- 4,500 W starting, 3,700 W running
- Inverter output
- CO sensor shutoff
Enough starting power for a sump pump and a fridge at once, still quiet.
Watch for: Check the CO sensor version; Westinghouse sells several iGen4500 variants.
Generac GP8000E COsense
Feeding a transfer switch for several circuits
- 10,000 W starting, 8,000 W running
- Electric start
- COsense shutoff
A common size for whole-circuit backup through a transfer switch or interlock.
Watch for: Loud, and not an inverter. Hook-up to house wiring needs an electrician.
DuroMax XP13000HX
Large homes with well pumps and 240 V loads
- 13,000 W starting on gasoline
- Gasoline or propane
- 120 V and 240 V outlets
One of the largest portable dual-fuel units, big enough for most essential circuits.
Watch for: Heavy, loud and thirsty. Needs a transfer switch for house circuits.
Battery carbon monoxide alarm
Every home that owns a generator
- Battery powered, so it works in an outage
- Place on every sleeping floor
Generator CO kills people every year in outages. A battery alarm is the cheapest protection.
Watch for: Replace the unit when it reaches end of life; check the date on the back.