No Heat in Winter: How to Stay Safe Until the Furnace Is Fixed

When the furnace stops in cold weather, the dangers while you wait for a repair are carbon monoxide from improvised heating, fires from space heaters, frozen pipes and hypothermia. Never heat the house with a gas oven, keep any generator or grill outdoors and well away from the house, keep space heaters at least 3 feet from anything that can burn, and let a faucet on an exposed pipe drip. Then call a heating contractor; renters should call the landlord or property manager, who arranges the repair.

What never to use for heat

A gas oven, a grill, a camp stove or a generator is not a heat source for a house. The Centers for Disease Control and Prevention (CDC) says that using a gas oven to heat your home puts everyone in it at risk of carbon monoxide (CO) poisoning.

CDC also warns never to use generators, grills or other gasoline-, propane- or charcoal-burning devices inside the home, the garage or a carport, or near doors, windows or vents. The U.S. Consumer Product Safety Commission (CPSC) says to run a portable generator outside only, at least 20 feet from the house.

The numbers explain the rule. CPSC reported in March 2026 that an average of nearly 100 people die in the U.S. each year from CO poisoning caused by portable generators.

Using a space heater without starting a fire

If you use a portable electric heater, give it space. CPSC says to keep the heater at least 3 feet from beds, clothes, curtains, papers, sofas and other items that can catch fire.

The rest of the CPSC and U.S. Fire Administration (USFA) rules are short:

• Plug the heater into a wall outlet, never a power strip, and never run the cord under a rug.
• Do not leave it running unattended in a confined space.
• Turn it off when you leave the room or go to bed.

The reason for the caution shows up in fire data. USFA reports that heating was the second most common cause of home fires in 2021, with an estimated 32,200 heating fires and about 190 deaths. Portable heaters were involved in only 3% of home heating fires in 2017 through 2019, but in 41% of the fatal ones.

Make sure the CO alarms work

A house with improvised heating is exactly where a CO alarm earns its place. CDC recommends battery-operated or battery-backup CO detectors near every sleeping area, and CPSC recommends testing CO and smoke alarms monthly.

Battery backup matters in a winter storm. If the power is out, an alarm that runs only on house power is silent.

After a snowstorm, USFA advises making sure the vents for the furnace, dryer, stove and fireplace are clear of snow and debris.

If a CO alarm sounds, CPSC’s advice is to move everyone outside to fresh air first and call 911 from there, not to look for the source.

Keeping the pipes from freezing

Pipes can freeze while the heat is off. Iowa State University Extension and Outreach, drawing on American Red Cross guidance, lists these steps among others:

• Let cold water drip from a faucet served by exposed pipes.
• Open kitchen and bathroom cabinet doors so warmer room air reaches the plumbing.
• Keep the thermostat at the same setting day and night once the heat is back.
• If you leave the house during cold weather, leave the heat set no lower than 55°F.

If a pipe does freeze, the same source says to keep the faucet open and warm the pipe with an electric heating pad, a hair dryer, a portable space heater kept away from flammable materials, or towels soaked in hot water. It warns never to use a blowtorch, a kerosene or propane heater, a charcoal stove or any other open flame.

Hypothermia: the signs to watch for

Cold indoors can become a health problem, and CDC lists the warning signs. In adults they are shivering, exhaustion or feeling very tired, confusion, fumbling hands, memory loss, slurred speech and drowsiness. In infants, CDC lists bright red, cold skin and very low energy.

CDC’s instruction is plain: if a person’s temperature is below 95°F, get medical attention right away. Anyone with a chronic health condition who has to stay in a cold house should ask a physician what precautions apply to them.

If you have to leave

Sometimes the practical choice is to stay somewhere warm until the repair is done. If you do, the heat setting in the empty house still matters: the 55°F floor from Iowa State University Extension applies once the furnace is running again, and the pipe steps apply while it is not.

Before leaving, make sure no space heater, generator or other temporary heat source is left running.

When a professional is needed, and what to ask

A furnace that will not run in freezing weather needs a heating contractor; the steps above only make the wait safer. The repair visit is also the moment to have the appliance’s combustion and venting looked at, since a fuel-burning furnace is one of the CO sources CDC names.

Questions worth asking:

• Will the visit include checks of gas connections, gas pressure, burner combustion and the heat exchanger? ENERGY STAR lists those for a heating checkup.
• If the furnace has to be replaced right away, how will the permit be handled? The model International Residential Code (Section R105.2.1) lets urgent equipment replacements and repairs go ahead, with the permit application due within the next working business day. Local rules can differ.
• Does the permit for this work bring a carbon monoxide alarm requirement? Under the 2021 and 2024 editions of that code, permitted work on fuel-fired equipment in an existing home calls for CO alarms placed as for a new home (Section R315.2.2 in 2021, R311.2.2 in 2024).
• What license do you hold for this work? The state or local agency that issues it can confirm it.

If the technician finds an unsafe condition, ask for it in writing, with the part involved.