Heating Your Home Without Power, Safely

Most furnaces need electricity to run, even gas ones: the blower, the igniter and the controls all run on power. So when an ice storm or blizzard takes the grid down in January, the house starts losing heat right away. How fast depends on the insulation and the weather, but a typical house can get uncomfortably cold within hours and dangerously cold within a day or two.

Every winter, people die in outages, and often not from the cold. They die from carbon monoxide, from heat sources that should never be used indoors. Here's how to stay warm and stay alive.

01The rule that matters most: carbon monoxide

Carbon monoxide (CO) is a colorless, odorless gas from anything that burns fuel. It can kill you in your sleep.

• Have battery-powered or battery-backup CO alarms on every level of the home and outside sleeping areas. Test them now, before winter.
• Never use these indoors, in a garage, or near a window: generators, charcoal or gas grills, camp stoves, outdoor propane heaters, or a car running in an attached garage.
• Never use a gas oven or stovetop to heat the house. The CDC specifically warns against it.
• Know the symptoms: headache, dizziness, nausea, confusion, sleepiness. If more than one person feels it, get everyone outside and call 911.

More on generator placement in generator safety.

02Safe(r) heat sources

A generator running the furnace

The best option if you have it: a generator outside, at a safe distance from the house, powering the furnace through a transfer switch or interlock. Most gas furnaces don't take a lot of power to run, so even a modest generator can often handle one. See how to size a backup generator and transfer switch vs. interlock.

Wood stoves and inserts

A properly installed wood stove is one of the best backup heat sources there is. Keep the chimney cleaned and inspected, and store dry wood. An open fireplace, on the other hand, sends a lot of heat up the chimney and can pull warm air out of the house; it helps in the room you're in, but not much more.

Indoor-rated propane heaters

Some small propane heaters are designed and labeled for indoor use, with an oxygen depletion sensor (ODS) and tip-over shutoff. Only use heaters specifically rated for indoor use, follow the manufacturer's ventilation instructions exactly (many still require cracking a window), and keep a CO alarm in the room.

Kerosene heaters

Kerosene heaters put out a lot of heat, but they burn fuel inside your home. If you use one:

• Check whether they're allowed where you live; some towns and states restrict them.
• Use only the correct grade of kerosene. Never gasoline.
• Ventilate as the manufacturer directs.
• Refuel outdoors, only when it's cool.
• Keep a CO alarm nearby.

Portable power stations and electric blankets

A battery power station can't run a space heater for long (heaters use a lot of power), but it can run an electric blanket or heated mattress pad for hours. That's a very efficient way to stay warm at night. See portable power station vs. generator.

03Fire safety

• Keep anything that burns at least 3 feet from heaters, stoves and fireplaces.
• Never leave a heater running when you leave the room or go to sleep, unless it's designed for that.
• Have smoke alarms and a fire extinguisher ready.
• Candles are a fire risk; use battery lanterns and headlamps for light.

04Cut how much heat you need

The less space you heat, the longer your fuel lasts:

• Pick one room and close it off, and seal it with blankets.
• Dress in layers, wear a hat indoors, and use sleeping bags rated for the cold.
• Hang blankets over doorways and windows.

05When to leave

If you can't keep the house safe and warm, go somewhere that is: a relative's house, a hotel, or a warming center. Towns and counties open warming centers in long outages; check local news, your town's alerts, or call 211.

Plan for a multi-day outage in winter; in the Midwest they're not rare. See how long Midwest power outages really last.

Photo: JapaneseKeroseneHeater by Douglas P. Perkins, CC BY 3.0.

Related: Your Neighbor's Generator and Your Bedroom Window