Will my gas furnace work during a power outage?

No. A gas furnace requires electricity for the ignition system, blower motor, and electronic controls. Without electricity, the furnace will not start even though the gas supply is still available. A portable generator of sufficient size (typically 1,500 to 2,500 watts to handle blower startup surge) can power the furnace, but the generator must be operated outdoors, at least 20 feet from any door, window, or vent. Never attempt to run a generator in a garage, even with the door open.

How quickly does a house cool down during a winter power outage?

A well-insulated house with good air sealing may lose only 1 to 2 degrees Fahrenheit per hour when outside temperatures are in the 20s. A poorly insulated older home can lose 3 to 5 degrees per hour or more. At that rate, a home starting at 68 degrees could reach 50 degrees in 4 to 6 hours and approach freezing within 12 to 18 hours. The rate of cooling depends on insulation quality, air leakage, window quality, outdoor temperature, and wind. Homes with large windows, poor insulation, or significant air leaks cool fastest.

Can I use my gas oven or stovetop for heat?

Never use a gas oven for heating. Gas ovens are not designed for continuous operation as space heaters and produce carbon monoxide during normal combustion. Running a gas oven with the door open in a closed house can build CO to dangerous levels within hours. The CPSC specifically warns against this practice. A gas stovetop burner produces less CO than an oven but is still not designed for space heating and presents a fire and burn hazard. Neither should be used as a heat source.

At what temperature should I worry about pipes freezing?

Pipes are at risk of freezing when they are exposed to temperatures of 20 degrees Fahrenheit or below for a sustained period. Pipes in exterior walls, unheated garages, crawl spaces, and attics are the most vulnerable. During a power outage in freezing weather, open cabinet doors under sinks on exterior walls to let warmer room air reach the pipes. If you have running water, let a thin trickle flow from one faucet served by an exposed pipe. If you must leave the house, shut off the main water valve and drain the system to prevent burst pipes.

How do I recognize hypothermia?

Early signs include shivering, confusion, slurred speech, drowsiness, and loss of coordination. Shivering is the body's first defense against cold, and its absence in a cold person is a danger sign because it means the body has lost the ability to generate heat through muscle contraction. In infants, watch for bright red, cold skin, and very low energy. Hypothermia is a medical emergency. Call 911. Move the person to a warm area, remove any wet clothing, and warm the center of the body first (chest, neck, head, groin) using blankets, dry clothing, or skin-to-skin contact. Give warm beverages if the person is conscious and alert. Do not give alcohol.

Home Self-Reliance Energy Heating During Outages

When the Power Goes Out

Safe warmth when the furnace stops.

Most heating systems require electricity. When the power goes out in winter, the house begins losing heat immediately. The decisions you make in the first few hours determine whether the outage is uncomfortable or dangerous.

First hour CO safety

Immediate Actions

The first hour without heat

Your home is a thermal battery. It holds heat for hours if you stop the losses early. These steps slow the cooling and buy you time to implement a longer-term plan.

Close off unused rooms

Shut every interior door to rooms you do not need. Stuff towels or blankets under the gaps. You are trying to reduce the volume of space that needs to stay warm. Pick one room as your warm room, ideally an interior room on the ground floor with few windows, and concentrate your household there.

Cover windows

Close all blinds and curtains. Windows are the thinnest part of your building envelope. If you have quilts, blankets, or even cardboard, hanging them over windows adds a layer of insulation. A single-pane window can lose heat ten times faster than an insulated wall. Covering it with any fabric slows the loss substantially.

Layer clothing

Put on layers now, before you feel cold. The body is a furnace that produces roughly 100 watts of heat at rest. Trapping that heat with layers is the simplest and most reliable warming strategy. Wear a hat, which prevents significant heat loss from the head. Wool and synthetic fleece insulate even when damp. Cotton does not.

Protect the pipes

Open cabinet doors under sinks on exterior walls so room air can reach the pipes. If you have running water, let a thin trickle flow from one faucet served by an exposed pipe. Moving water freezes slower than standing water. If temperatures will drop below 20 degrees Fahrenheit and the outage may last more than a few hours, consider shutting off the main water valve and draining the system.

Gather supplies in the warm room

Bring blankets, sleeping bags, flashlights, water, snacks, medications, phone chargers, and a battery-powered radio to your chosen warm room before the rest of the house gets cold. Moving through a cold house later to retrieve forgotten items wastes body heat and is harder than it sounds when you are already chilled.

Safe Options

Indoor heating that will not kill you

Not every heat source is safe indoors. The wrong choice produces carbon monoxide, a colorless, odorless gas that kills an average of nearly 100 Americans per year from portable generators alone.^[1] This section lists only options that are safe for indoor use when properly installed and operated.

Wood stove or fireplace insert

A properly installed wood stove with a functioning chimney is the most effective non-electric heating option. It can heat a large room or an entire small house. Requires seasoned firewood, a clean chimney (have it inspected annually), and a working damper. Keep a fire extinguisher nearby. Never burn treated wood, painted wood, or trash in a wood stove.

Our wood heat guide covers stove selection, fuel, and safety in depth.

Electric space heater (with generator or battery)

If you have a generator or large portable power station, an electric space heater produces no combustion byproducts indoors. A standard 1,500-watt ceramic heater can warm a small room effectively. Use one with a tip-over shutoff and overheat protection. Keep it 3 feet from anything flammable. Never plug a space heater into an extension cord or power strip.

The generator must be outdoors, at least 20 feet from the house, with the cord running through a window or door.

Propane heater rated for indoor use

Some propane heaters are specifically designed, tested, and rated for indoor use. These include vent-free wall-mounted heaters with oxygen depletion sensors (ODS) and certain portable propane heaters marked "indoor safe" with ODS and tip-over shutoff. The ODS automatically shuts the heater off if oxygen levels drop. Verify the "indoor use" rating on the label before using any propane heater inside.

Even with an ODS, always crack a window for ventilation and ensure your CO detector is working.

Generator powering the furnace

A portable generator of 2,500 to 3,500 watts (to handle blower startup surge) can power most gas furnaces. The generator stays outdoors, at least 20 feet from any door, window, or vent, with the exhaust pointed away from the house. Connect through a heavy-duty outdoor-rated extension cord or a transfer switch installed by an electrician. Never backfeed power into your breaker panel without a transfer switch.

The Invisible Killer

Carbon monoxide: the rules that save lives

Carbon monoxide (CO) is produced whenever fuel burns: gasoline, propane, natural gas, wood, charcoal, kerosene. It is colorless and odorless. You cannot see it, smell it, or taste it. CO poisoning can cause unconsciousness within minutes and death shortly after. The CPSC reports that generators and portable heaters are the leading sources of CO deaths in homes, and the largest percentage of generator-related CO deaths occur during winter power outages.^[1]

Never use these indoors for heat

Portable generator. Not in the house, garage, basement, crawl space, or shed. Not with the door open. At least 20 feet from any opening.^[2]
Charcoal grill or hibachi. Charcoal produces extreme CO levels. People die from this every winter.
Propane or gas camp stove. Designed for outdoor use with natural ventilation.

Gas oven. Not designed for space heating. Produces CO during normal operation. Running it with the door open in a closed house is dangerous.
Propane heater not rated for indoor use. Check the label. If it does not say "indoor use" and does not have an ODS, it belongs outside.
Kerosene heater (in most states). Some states allow kerosene heaters indoors with specific ventilation. Many prohibit them. Check your state and local codes.

CO detectors save lives

Install battery-powered CO detectors on every level of your home and outside each sleeping area. Test them monthly. Replace batteries at least annually. Replace the detector itself every 5 to 7 years (check the manufacturer's recommendation on the back of the unit). During a power outage, your hardwired CO detectors may not work unless they have battery backup. A battery-operated detector is your last line of defense.

CO poisoning symptoms

Headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. Because these symptoms resemble the flu, people often do not recognize CO poisoning until it is severe. If the CO alarm sounds, or if multiple people in the house develop these symptoms simultaneously, get everyone outside immediately and call 911. Do not go back inside to look for the source.^[3]

Heat Retention

Keeping the heat you have

Even without a heat source, you can slow how fast your house cools. Every degree you retain extends your comfort window and your decision window.

The one-room strategy

Choose one room as the family warm room. Ideally: interior (fewer exterior walls), ground floor (heat rises and escapes through the roof faster), small (easier to warm with body heat alone), and away from large windows. Close and seal all other rooms. Four people in a small room with the door closed and a blanket over the window can maintain a room temperature 10 to 15 degrees above the rest of the house through body heat alone.

Sleeping warm without heat

Sleep in layers. Use sleeping bags inside sleeping bags if you have them. Place insulation underneath you as well as on top: a camping pad, folded blankets, or even couch cushions on the floor. You lose as much heat through the surface you lie on as through the air above you.

A sleeping bag rated to 30 or 40 degrees Fahrenheit is sufficient for most indoor winter outage scenarios. Sleeping bags rated to 0 degrees are designed for camping and are more than adequate indoors.

Hot water bottles and hand warmers

If you can boil water (camp stove outdoors, wood stove, or generator-powered kettle), a hot water bottle or a sealed container of hot water wrapped in a towel provides direct body heat for 2 to 4 hours. Place it at your core (chest, abdomen) or feet. Disposable chemical hand warmers (iron-powder type) provide 8 to 12 hours of heat and cost about $1 per pair. These are worth stocking before winter.

Protect the House

Preventing frozen pipes

A burst pipe from freezing can cause thousands of dollars in water damage. During a winter outage, pipe protection is as important as personal warmth. Water expands when it freezes, and the pressure can split copper, PVC, and PEX pipes.

Most vulnerable pipes

Pipes in exterior walls, unheated garages, crawl spaces, attics, and near exterior hose bibs. Pipes in interior walls are generally safe as long as the house stays above freezing. The risk increases sharply when air temperature around the pipe drops below 20 degrees Fahrenheit and stays there.

If you have running water

Open cabinet doors under sinks on exterior walls. Let a thin trickle of water run from one or two faucets served by the most exposed pipes. Moving water resists freezing. The water does not need to be hot; a cold trickle is sufficient. Set the faucet to a steady drip, slightly more than one drop per second.

If you are leaving the house

If you evacuate to a warmer location, shut off the main water valve and drain the system. Open all faucets, flush toilets, and drain the water heater (if it is safe to do so and the heater is off). This removes the water that would freeze and burst the pipes. When power returns and you return home, close faucets, open the main valve slowly, and check for leaks before restoring full pressure.

If a pipe freezes but has not burst

Open the faucet served by the frozen pipe. Apply gentle heat to the frozen section using a hair dryer (if you have power or a generator), warm towels, or a portable space heater directed at the area. Start from the faucet end and work toward the frozen section. Never use an open flame, propane torch, or blowtorch on a frozen pipe. The pipe can burst from steam pressure, or nearby materials can catch fire.

Recognize the Danger

Recognizing hypothermia and frostbite

Hypothermia can develop indoors. A house at 50 degrees Fahrenheit with a person who is elderly, sedentary, inadequately dressed, or wet is a hypothermia risk. You do not need to be outdoors in a blizzard. The CDC defines hypothermia as a body temperature below 95 degrees Fahrenheit.^[4]

Hypothermia

Early signs: Shivering, confusion, slurred speech, drowsiness, loss of coordination, fumbling hands.

Late signs: Shivering stops (a danger sign), stiff muscles, very slow breathing, loss of consciousness.

In infants: Bright red, cold skin and very low energy.

Response: Call 911. Move to a warm area. Remove wet clothing. Warm the center of the body first: chest, neck, head, groin. Use blankets, sleeping bags, or skin-to-skin contact under dry blankets. Give warm (not hot) beverages if conscious. Do not give alcohol. Do not rub extremities. Handle gently.

Frostbite

Early signs (frostnip): Red or pale skin, tingling, numbness in fingers, toes, nose, ears, or cheeks. Reversible at this stage.

Advanced signs: White or grayish-yellow skin, hard or waxy texture, numbness, blistering after rewarming.

Response: Move indoors. Do not rub the affected area; rubbing damages frozen tissue. Immerse in warm (not hot) water, 100 to 104 degrees Fahrenheit, or apply warm cloths. Do not use direct heat (heating pad, fire, stove) because frostbitten skin burns easily and the person may not feel it. Seek medical attention for any frostbite beyond frostnip.^[5]

Who is most vulnerable

Adults over 65 (reduced ability to sense cold and regulate temperature), infants (lose body heat faster than adults), people with chronic conditions (heart disease, diabetes, thyroid disorders), people who have consumed alcohol (dilates blood vessels and increases heat loss while reducing awareness of cold), and people on certain medications (sedatives, psychiatric medications).

The Decision

When to leave and where to go

Leaving a cold house for a warmer location is not a failure. It is the correct decision when staying becomes dangerous. Make the decision while you can still drive safely, while roads are passable, and before anyone in the household is in distress.

Decision triggers

Leave if: indoor temperature is below 50 degrees and falling with no heat source, the outage is expected to last overnight or longer in freezing conditions, anyone in the household is elderly, an infant, or has a condition that makes cold exposure dangerous, or you do not have an adequate heat source and supplies to maintain a warm room through the night.

Where to go

Family or friends with power, a hotel or motel (book early because rooms fill fast during regional outages), a designated warming shelter (check with local emergency management, 211, or local news), or a community building with backup heat (some churches and community centers open during cold emergencies).

Before you leave

Shut off the main water valve and drain the system if temperatures will drop below freezing. Turn off or unplug appliances to prevent a power surge when electricity is restored. Leave one light on so you can see from outside when power returns. Take medications, important documents, phone chargers, and warm clothing.

Build the Capability

Before next winter

The best time to prepare for a winter outage is during mild weather when there is no urgency and equipment is in stock.

Battery CO detectors

Install on every level and outside every bedroom. Test monthly. This is the minimum non-negotiable preparation for winter outages.

Insulation and air sealing

Every dollar spent on insulation and air sealing slows heat loss during outages and reduces your heating bill the rest of the year. Weatherstripping, caulk, and attic insulation are the highest-return improvements.

Generator or battery backup

A generator that can power your furnace blower keeps the whole heating system running. Our generator guide and measuring power use guide cover sizing.

Sleeping bags and blankets

Keep enough sleeping bags or heavy blankets for every household member. Rated to 30 to 40 degrees Fahrenheit is sufficient for indoor use. Store them accessible, not buried in the attic.

Know your main water shutoff

Locate it now, label it, and make sure it turns. Our utility shutoffs guide covers all three shutoffs every household member should know.

Firewood or propane

If you have a wood stove, stock seasoned firewood before winter. If you have a propane system, keep the tank above 30 percent. If you plan to use an indoor-rated propane heater, stock fuel canisters before the season.

Sources

CPSC. "Non-Fire Carbon Monoxide Deaths Associated with Consumer Products." cpsc.gov. Accessed August 2026.
CPSC. "Portable Generator Safety." cpsc.gov. Accessed August 2026.
CDC. "Carbon Monoxide Poisoning: Prevention Tips." cdc.gov. Accessed August 2026.
CDC. "Hypothermia: Prevention." cdc.gov. Accessed August 2026.
CDC. "Frostbite: Prevention and Treatment." cdc.gov. Accessed August 2026.
NFPA. "Heating Safety." nfpa.org. Accessed August 2026.

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