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Generator safety: how to use a portable generator during a power outage
- Run it outdoors only, at least 20 feet from the house, exhaust pointed away from doors, windows and vents — never in a garage, basement, crawlspace or shed, even with the door open.
- Have battery-powered carbon monoxide alarms working inside the home.
- Never plug a generator into a wall outlet ("backfeeding"). Use cords or a transfer switch installed by an electrician.
- Let it cool before refueling.
Portable generators are one of the most useful tools in a long outage — and one of the most dangerous. A single generator produces as much carbon monoxide (CO) as hundreds of cars idling. CO is invisible and odorless, and every year people die after running generators in garages or too close to windows. These rules come from the CDC and the Consumer Product Safety Commission.
1. Where to put the generator
- Outdoors, on a dry, level surface, at least 20 feet from your home and your neighbors' homes.
- Point the exhaust away from any doors, windows, vents and air intakes.
- Protect it from rain with a canopy or tent designed for generators that stays open on all sides — never put it in an enclosed space to keep it dry.
- Consider a security chain; generators are frequently stolen during outages.
2. Carbon monoxide: alarms and warning signs
Install battery-powered or battery-backup CO alarms on every level and outside sleeping areas, and test them before you start the generator. Symptoms of CO poisoning are often mistaken for the flu: headache, dizziness, weakness, nausea, vomiting, chest pain and confusion. People who are asleep can die before they notice anything.
If an alarm sounds or anyone feels sick: get everyone into fresh air immediately, call 911, and don't go back inside until responders say it's safe.
3. Connecting appliances safely
- Never backfeed by plugging the generator into a wall outlet or the dryer outlet. It can send power back through the lines and electrocute utility workers or neighbors, and it can damage your home's wiring or start a fire.
- Plug appliances directly into the generator, or use heavy-duty, outdoor-rated extension cords rated for the load (check the wattage and gauge on the label). Inspect cords for cuts and keep them out of standing water.
- To power home circuits, have a licensed electrician install a transfer switch or interlock kit and get it inspected where required.
- Don't overload the generator — add appliances one at a time.
4. Fuel and refueling
- Turn the generator off and let it cool before refueling. Gasoline spilled on hot parts can ignite.
- Store fuel outside living areas, in approved containers, away from fuel-burning appliances like water heaters.
- Use fuel stabilizer for gasoline you store for more than about a month, and run the generator for a short time every few months to keep it in working order.
5. How big a generator do you need?
Add up the running watts of what you need at the same time, and make sure the generator can handle the largest starting (surge) watts — motors like fridges and pumps need 2–3 times their running watts to start. Figures below are typical ranges; always check the label on your own appliances.
| Appliance | Typical running watts | Typical starting watts |
|---|---|---|
| Refrigerator | ~600–800 | ~1,500–2,200 |
| Chest freezer | ~500–700 | ~1,000–1,500 |
| Sump pump (1/2 hp) | ~800–1,000 | ~1,500–2,200 |
| Furnace fan (gas furnace) | ~500–800 | ~1,000–2,300 |
| Well pump (1/2 hp) | ~1,000 | ~2,000+ |
| Window AC (10,000 BTU) | ~1,200 | ~1,800 |
| LED lights (several) | ~50–100 | — |
| Phone/laptop charging | ~20–100 | — |
| CPAP machine | ~30–60 | — |
Most households can keep a fridge, a freezer, lights, phones and a furnace fan going with a 3,500–5,000 watt generator, run in turns. Inverter generators are quieter, use less fuel and are safer for electronics.
Alternatives for apartments and indoor use
If you can't safely place a gas generator 20 feet from your home — common in apartments, condos and townhouses — consider a battery power station (often LiFePO4), recharged by solar panels or from your car. They produce no exhaust and can be used indoors to run phones, lights, a CPAP, an electric blanket or a small fridge for limited periods.
Generator FAQ
How far should a generator be from the house?
At least 20 feet, with the exhaust pointed away from doors, windows and vents — and never inside any enclosed or partly enclosed space.
Can I plug a generator into a wall outlet?
No. That's backfeeding, and it can kill utility workers or neighbors. Use extension cords or a professionally installed transfer switch.
Can I run a generator in the rain?
Only under a generator cover that keeps it dry while staying open on all sides, on a dry surface, with dry hands.
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