Portable Generators for Home Backup: Sizing, Safety, Specs

A portable generator can keep a fridge, a sump pump and a few lights going through a long outage. It also makes carbon monoxide, which is why every section below comes back to placement. This is general information, using official safety guidance and each maker’s own published specs as I read them on November 9, 2026. I haven’t tested these generators, and this isn’t a ranking.

Carbon monoxide warning. A generator’s exhaust contains carbon monoxide (CO), which you can’t see or smell. CPSC says more than 80 people die each year in the US from CO poisoning caused by portable generators, and that running one indoors can kill in minutes. Never run a generator inside a home, garage, basement, crawlspace, shed or porch, even with doors and windows open. CDC says to keep it more than 20 feet (6 m) from any window, door or vent, and Canada.ca says at least 6 m (20 feet) from all buildings. Put battery-powered or battery-backup CO alarms near every sleeping area. If anyone feels dizzy, sick or weak, get to fresh air and call 911.

Inverter or conventional

Most portable generators fall into two groups.

• Inverter generators turn the engine’s power into AC electronically. In the table below they list 1,800 to 4,000 running watts, weigh roughly 47 to 100 lb (21 to 46 kg), and list noise figures from 48 to 64 dBA. WEN lists total harmonic distortion under 1.2% at full load for its DF480iX, a figure makers publish for sensitive electronics.
• Conventional (open-frame) generators in the table list 8,000 to 10,500 running watts and weigh 198 to 240 lb (90 to 109 kg). They can cover more of a home at once, including 240 V loads through the right outlet and transfer equipment.

Neither type is safer indoors. Both burn fuel and make CO.

Dual fuel and tri fuel

A dual-fuel generator runs on gasoline or propane. A tri-fuel model adds natural gas. The makers here list lower output on propane: Champion’s 201531 goes from 3,250 running watts on gasoline to 2,925 on propane, and DuroMax’s XP13000HXT from 10,500 to 10,000. Run times change too. Champion lists 10 hours on gasoline and 25 hours on a 20 lb propane tank at quarter load.

Propane cylinders also stay outdoors. CPSC says to keep propane, gasoline and kerosene outside living areas.

Size it by watts

Two numbers matter, and both are on the generator’s spec sheet:

• Running watts: what it can supply continuously.
• Starting (surge or peak) watts: the short burst for motors that kick on, like a fridge compressor or pump.

The Eugene Water & Electric Board’s sizing sheet gives a simple method: add the running watts of everything you want on at once, then add the single biggest extra starting load. Using that sheet’s typical figures:

Appliance (EWEB typical figures)	Running watts	Extra starting watts
Refrigerator/freezer	700	2,200
Sump pump, 1/2 hp	1,050	2,200
Furnace fan, 1/3 hp	700	1,400
Four 15 W LED bulbs	60	none

Running total: 700 + 1,050 + 700 + 60 = 2,510 W. Add the biggest extra starting load, 2,200 W, and you need about 4,710 W of starting capacity. The sheet calls this a guide only. Your own appliance labels are better, and an electrician can measure.

Six models and their published specs

Figures come only from each maker’s own product page. Where a page left a figure out, the table says so. Run times are at the load the maker states.

Output, fuel and CO shutoff

Model	Fuel	Running W	Starting W	CO shutoff
Honda EU2200i	Gasoline	1,800	2,200	Yes, CO-MINDER
Champion 201531	Gas / propane	3,250 / 2,925	4,500 / 4,500	Yes, CO Shield
Westinghouse iGen4500DFcv	Gas / propane	3,700 / 3,330	4,500 / 4,050	Yes
WEN DF480iX	Gas / propane	4,000 / 3,600	4,800 / 4,320	Yes, CO Watchdog
Generac GP8000E (7715)	Gas powered	8,000	10,000	Yes, COsense
DuroMax XP13000HXT	Gas / propane / natural gas	10,500 / 10,000 / 9,000	13,000 / 12,500 / 11,250	Yes

Type, run time, noise and weight

Model	Type	Run time (maker)	Noise (maker)	Weight
Honda EU2200i	Inverter	8.1 h at 1/4 load	48 dBA at 1/4 load, 57 at rated	47.4 lb (21.5 kg)
Champion 201531	Inverter	10 h gas, 25 h propane at 1/4 load	64 dBA at 23 ft (7 m)	51.8 lb (23.5 kg)
Westinghouse iGen4500DFcv	Inverter	Up to 18 h at 25% load	“As low as” 52 dBA	100.3 lb (45.5 kg)
WEN DF480iX	Inverter	Up to 7 h gas, 12 h propane (20 lb) at 1/2 load	62 dB at 1/4 load	Not listed on WEN’s page
Generac GP8000E (7715)	Conventional	10 h at 50% load*	Not listed	198 lb (90 kg)
DuroMax XP13000HXT	Conventional	8.5 h gas, 6.5 h propane at 50%	74 dB	240 lb (109 kg) dry

* Generac’s spec table says 10 hours; its description on the same page says up to 11. Generac’s model name includes “49ST/CSA”. Noise figures aren’t measured the same way across makers, so compare them only loosely.

Using the example above, a 4,710 W starting need rules out the EU2200i on its own and is close to the limit of the 4,500 W inverters. The conventional models cover it with room to spare.

Transfer switches, and why backfeeding is dangerous

Never plug a generator into a wall outlet. CPSC calls this backfeeding. It says the practice can electrocute utility workers and neighbours served by the same transformer, and it bypasses your home’s circuit protection. OSHA adds that a generator tied into a building without a properly installed transfer switch can energize lines over long distances.

You have two safe options:

1. Plug appliances straight into the generator with heavy-duty extension cords made for outdoor use. CPSC says each cord should be undamaged, have three prongs, and be rated above the load on it.
2. Have a licensed electrician connect it to your home’s wiring. Canada.ca says a backup generator may only be connected to your home’s electrical system through an approved transfer panel and switch installed by a qualified electrician. In Ontario, the Electrical Safety Authority’s notice on portable generators says any setup must make backfeeding the utility lines impossible. Ask your electrician about permits where you live.

Fuel storage and maintenance

• Refuel cold. CPSC and OSHA both say to turn the generator off and let it cool before adding fuel. Spilled gasoline on a hot engine can ignite.
• Store fuel outside living areas. CPSC says never store generator fuel in the home. Use labelled, non-glass safety containers and keep them away from fuel-burning appliances like a garage water heater.
• Treat stored gasoline. Honda says to add stabilizer to your fuel container each time you fill it, not to use fuel with more than 10% ethanol in its generators, and that stabilizer can’t bring back stale fuel.
• Store the generator properly. Honda’s guidance depends on how long it will sit. For storage of 2 to 12 months it says to drain the carburetor; for over a year, drain the tank and carburetor. Champion says gasoline left in the carburetor can clog it if the unit isn’t used or drained within two weeks.
• Check your CO alarms. CDC says to check their batteries each spring and fall and replace the alarm per the maker’s instructions or every 5 years.

Follow your own owner’s manual for oil changes and how often to run the generator.

Is a generator the right fit?

If you mainly need a fridge, phones, lights and a CPAP, a battery station may fit better. My comparison of generators and power stations walks through the trade-offs, and my power station sizing guide does the battery math. The generator safety guide has the full safety checklist, and backup power basics covers the options side by side.

To see everything I’d keep on hand, go to my picks, or build a list for your household in the plan builder. The 14-day power outage list is a good place to start.