Portable Generators, Explained

This is the single most important rule and it outranks every spec: a running generator produces carbon monoxide, an invisible, odorless gas that can kill within minutes. Never run a generator indoors, in a garage, in a shed, on a covered porch, or in any partially enclosed space, even with the doors and windows open, ventilation does not make it safe. Place it outdoors on dry ground, well away from the house (at least 20 feet is the widely recommended distance), and point the exhaust away from all doors, windows, and vents so fumes can't drift back inside. Strongly favor a model with a built-in CO auto-shutoff sensor, which automatically kills the engine if CO builds up, but treat that sensor as a backstop, not a license to place the unit carelessly. Also install battery-powered CO alarms inside your home. If anyone feels dizzy, nauseous, headachy, or weak while the generator is running, get everyone to fresh air immediately.

Add up the running watts of everything you truly need on at once. Bare essentials, a fridge, a few lights, Wi-Fi, and phone chargers, often total under 2,000 running watts, which a compact inverter handles easily. Add a furnace blower, a sump or well pump, and a window AC and you're realistically in the 7,000-to-9,500 running-watt range, where a dual-fuel whole-home unit shines. Then make sure your peak (starting) wattage clears the surge of your largest motor, since fridges, pumps, and AC briefly draw several times their running watts at startup. Sizing to your real simultaneous loads, rather than to the biggest number you can afford, is how you avoid overpaying.

Conventional (open-frame) generators run the engine at a fixed speed to make power directly, they're the most output-per-dollar but louder and produce higher-THD ('dirtier') power. Inverter generators condition the output down to very low THD (under about 3%), making them quieter and safe for sensitive electronics like laptops and modern TVs, at a higher price per watt. 'Dual fuel' is a separate axis entirely: it describes the fuel source (gasoline or propane), not the power type. A generator can be dual-fuel and conventional, or dual-fuel and an inverter.

For a handful of devices, run heavy outdoor-rated extension cords from the generator to each appliance. To power hardwired circuits like a furnace or well pump, have a licensed electrician install a manual transfer switch or an interlock kit at your panel. Never plug a generator into a wall outlet to 'backfeed' the house, it can electrocute utility workers down the line and destroy your equipment. Use the transfer switch to isolate your home from the grid whenever the generator is running.

Don't operate a generator in rain or standing water unprotected. Use a purpose-made open-sided generator cover or canopy that shields it while still allowing airflow and heat to escape, and always plug into GFCI-protected outlets. For fuel, dual-fuel units have a real edge: propane stores for years without going stale, while gasoline should be treated with stabilizer and rotated so it doesn't gum up the carburetor. Store fuel in approved containers away from living spaces and ignition sources, and always let the engine cool before refueling.

Yes. Human error is exactly what the sensor protects against, running too close to an open window, tucking it under an overhang during a storm, or a wind shift blowing exhaust back toward the house. The sensor is an automatic backstop that shuts the engine down before CO reaches dangerous levels, and in 2026 there's no good reason to buy a unit without one. Just remember it's a second line of defense: correct outdoor placement, far from doors and windows, is still the first.