Does a Gas Furnace Work During a Power Outage?
No. A modern gas furnace burns gas for heat, but it needs electricity to run. Carrier's troubleshooting guide for one of its gas furnaces has the control board check for 115-volt and 24-volt power, and the blower motor, draft inducer and hot surface igniter are all electric parts. When the power goes out, the furnace stops, even with gas still flowing to the house.
A generator can keep it running, but only if it is connected the right way. The U.S. Consumer Product Safety Commission said in December 2025 that about 100 people die in the U.S. each year from carbon monoxide poisoning tied to portable generators, and it says to run them outside only, at least 20 feet from the house. The American Red Cross says to have an electrician install a power transfer switch in line with the National Electrical Code, warns that some machines draw up to 3 times as much power when starting up, and calls a permanently installed stationary generator the best option. This guide covers why furnaces need power, how to run one on a generator safely, and what to do until the lights come back.
Why Does a Gas Furnace Need Electricity?
Gas supplies the heat, and electricity runs the parts that make the heat safe and usable. In the Carrier furnace covered by its troubleshooting guide, the control board runs on 115-volt line power and 24-volt control power. The draft inducer motor clears the vent before ignition, the hot surface igniter lights the burners, and the blower pushes warm air through the ducts.
Without power, none of those steps can happen, and the furnace's safety controls will not let the burners fire. Older furnaces with a standing pilot light still rely on an electric blower to move heat through the house. Trane says an older furnace installed before 2010 may have a standing pilot.
If your furnace does not come back on after an outage, the guide to a furnace that won't turn on covers the checks to try first.
Can You Run a Furnace on a Generator?
Yes, with the right connection. A transfer switch is an electrical switch, installed by an electrician, that lets a generator feed selected household circuits while keeping the home disconnected from the utility lines. The Red Cross recommends one, installed in accordance with the National Electrical Code, for anyone who wants to connect a generator to house wiring.
The Red Cross is just as clear about what not to do. Never try to power the house wiring by plugging a generator into a wall outlet. That practice, called backfeeding, puts utility workers, neighbors and your household at risk of electrocution.
Sizing comes next. The Red Cross says to add up the power requirements of everything you plan to run, and to remember that some machines draw up to 3 times as much power when starting. The furnace's data plate lists its electrical rating, and an electrician can size the generator and switch to match. The Red Cross names a permanently installed stationary generator as the best option. The guide to when a backup generator should be installed covers the cooling side of the same decision.
Where Should a Portable Generator Go?
Outside, and well away from the house. CPSC's December 2025 safety guidance says:
Never operate a portable generator inside a home, garage, basement, crawlspace or shed. Opening doors and windows does not make it safe.
Run it outside only, at least 20 feet from the house, and not on a porch or in a carport.
Point the exhaust away from the home.
Look for a model with a carbon monoxide shut-off feature.
Install carbon monoxide alarms on each level of the home and outside sleeping areas, ideally interconnected, and test them monthly.
Ready.gov, which updated its power outage guidance in June 2026, adds that generators and fuel belong at least 20 feet from windows, doors and attached garages. The guide to preventing carbon monoxide from your furnace covers the furnace side of carbon monoxide safety.
Do Boilers, Oil Burners and Heat Pumps Need Power Too?
Yes. A heat pump runs on electricity, so an outage stops it along with its backup heat. Oil burners use electric controls and motors, and Beckett's manual for its AF and AFG oil burners warns that a power failure while a house is unattended in severe cold can freeze plumbing in a matter of hours. Hydronic heaters fed by a boiler, such as Modine's ceiling-mounted garage unit, run on 115-volt power for their fans.
Somerset County gets that kind of cold. NOAA's 1991 to 2020 climate normals show the Meyersdale station averaging 8.2 nights a year at or below 0°F and 26.2 nights at or below 10°F. An outage on one of those nights puts pipes at risk quickly.
How Do You Stay Warm Until the Power Comes Back?
Ready.gov and CPSC give these steps:
Do not use a gas stove or oven to heat your home.
Check with local officials about heating and cooling locations open near you.
If you run a portable electric heater on a generator-backed circuit, keep it 3 feet from anything that can burn and plug it directly into a wall outlet, never a power strip, as CPSC advises.
If you smell gas, leave the home and call the gas company from outside. Do not operate lights, phones or other electronics inside.
The guide to what to do when your heat goes out in winter has more steps for Somerset County homes.
What Should Happen When the Power Returns?
The furnace should start on the next call for heat. On the Carrier furnace in its troubleshooting guide, status code 12 means the blower runs for 90 seconds after power returns, which is normal. Give the system a few minutes before deciding something is wrong.
If the furnace still will not heat, check the breaker and confirm the thermostat is set to heat. If the furnace shows an error code or stays off, note the flash pattern and call a technician.
FAQ
Does a gas furnace with a pilot light work without power?
The pilot may stay lit, but the blower that moves heat through the ducts is electric. Without power, the house will not get warm air.
What size generator do I need to run a furnace?
The Red Cross says to add up the power needs of everything you plan to run and plan for starting surges up to 3 times the running load. An electrician can size it from your furnace's data plate.
Can I plug my furnace into a generator?
Only through a proper connection. The Red Cross recommends a transfer switch installed by an electrician and warns never to backfeed house wiring through a wall outlet.
Is it safe to heat the house with a gas oven?
No. Ready.gov says not to use a gas stove or oven to heat your home.
How far should a generator be from the house?
CPSC and Ready.gov both say at least 20 feet, outside only, and away from windows, doors and attached garages.
Can pipes freeze during a winter power outage?
Yes. Beckett warns that plumbing can freeze in a matter of hours when heat stops in severe cold and no one is home.
Van Bremen's Heat & Air Gets Furnaces Running Again
Van Bremen's Heat & Air repairs and maintains furnaces, boilers and heat pumps from its office at 214 Stoystown Rd in Somerset, serving Somerset, Fayette, Cambria and Westmoreland Counties and Morgantown, WV. If a furnace will not restart after an outage, a technician can check the control, igniter and safeties. See the heating services page for more.
Visit Van Bremen's Heat & Air or call (814) 483-1735 today. Contact us for more information.
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