What happens to a gas heater when the power goes out?

Author: Mr. Bernardo Smith  |  Last update: Friday, July 11, 2025

Your gas furnace does not operate like a stove because it needs electricity to generate the heat necessary to warm your house. A gas furnace is ineffective during a power outage because it needs electricity to power the components that make it work.

Will my gas heat work if the power goes out?

Like most modern appliances, your gas furnace does use some amount of electricity to operate. Unfortunately, this means that your gas furnace will not work during a power outage. You should know how to safeguard your furnace for those times when the power goes out. You should also have a backup plan for your home.

Will a gas furnace come back on after a power outage?

In summary, while a gas furnace may still produce heat during a power outage (if it has a standing pilot light), it will not be able to effectively heat the home without electricity for the blower fan and other components.

Does gas still run during a power outage?

There is a common misconception that gas appliances are better because they keep working when the lights go out. While natural gas can still flow into your home during a blackout, many appliances still require power to operate.

Are gas heaters connected to electricity?

And one of the reasons for all these benefits is that gas furnaces have key electrical components. They don't use electricity to heat the air, but they do use electricity to run. As we mentioned before, this is beneficial.

Furnace 101 when the power goes out

Will my gas stove work if the power goes out?

Gas stoves use gas to power heating elements inside the oven and burners on the stovetop, but they rely on electricity for ignition. Though you can usually bypass electric ignitions and light gas cooktops manually, other parts of the stove will not work without electricity.

How does a gas heater get power?

A gas heater works by burning natural gas or propane to generate heat. Cold air from the home's ductwork enters the heater and is warmed up by a heat exchanger. The hot air is blown throughout the home via the ducts, and the exhaust is blown out of the furnace through a vent to the outside of the home.

How to run a furnace when the power is out?

Portable Generator

Connect a heavy-duty double-pole, double-throw switch to the furnace, along with a power inlet receptacle. If the utility power goes out, flip the double-pole switch to disconnect the permanent furnace circuit, and the run a cord from the portable generator to the inlet.

Will a gas water heater work if electricity goes out?

Most natural gas water heaters work without electricity.

Do you lose gas when you lose power?

The Gas Valve Shuts Off

Because it's not safe to try to light many furnaces without electricity, the furnace will sense when there's no power, and the gas valve will close, cutting off the flow of gas and preventing the furnace from functioning. This safety feature is something you should appreciate, not tamper with.

How to reset gas furnace after power outage?

The Furnace Needs a Rest

Simply go to your breaker box, switch the breaker off, wait 30 seconds, and turn it back on. Next, If you have a gas furnace, shut off the unit's pilot light and wait until the gas disperses. Finally, push the furnace's reset button to restore its power and operations.

Is it okay to turn off power to gas furnace?

You can switch off the pilot light by turning the knob to the off position. To uphold safety, you can turn off the gas supply to the furnace. But be careful not to turn off the gas supply to the rest of the house. You'll still need it for cooking, cleaning, heating water, and other activities in summer.

How to stay warm if power goes out in winter?

If there's no electricity or gas, you can stay warm with blankets and sleeping bags. You should stay in a small, well-insulated room with other people to help retain body heat. Find air leaks and place towels around them to reduce heat loss.

Will gas furnace come back on after power outage?

A System Reset Is Necessary

A furnace not working after a power outage may need a reset, and most modern furnaces have a yellow or red reset button. You'll need to reset your furnace's breaker first. Next, homeowners with gas furnaces should turn off the pilot light and allow the gas to disperse.

How do I heat my house if the power goes out?

Wood Stoves and Fireplaces

These are excellent sources of heat during a power outage. Stocking up on dry, seasoned wood before winter hits ensures you have fuel to keep your house warm. Wood stoves are particularly efficient, providing heat for extended periods and requiring little maintenance once set up.

Do I need to relight my furnace after gas shut off?

Because your pilot light relies on natural gas to stay aflame, shutting your gas off will also make your pilot light go out. Luckily, this simple matter can be solved by turning your gas back on and re-lighting the pilot light yourself.

Does gas heat work when power is out?

Your gas furnace does not operate like a stove because it needs electricity to generate the heat necessary to warm your house. A gas furnace is ineffective during a power outage because it needs electricity to power the components that make it work.

Can I flush the toilet if the power is out?

Depending on the amount of water remaining in the pipes, you might be able to flush your toilet several times while the power is out. Eventually, however, your tank won't fill up anymore because the pumps are down. When this happens, you will need to flush your toilet manually by pouring in a bucket of water.

Will gas still work without electricity?

Unfortunately, without electricity, even a gas-powered furnace will not work during an outage. Circuit boards, blower motors, and other aspects of your appliance all require electricity to get the heat flowing.

Do I need to relight my furnace if the power goes out?

For example, do you have to relight furnace after power outage? Yes, if your pilot light goes out, you will want to shut off the gas line and wait for power. Let's take a look below at some steps you can take to stay safe if your furnace loses power.

Will a gas water heater work without power?

Gas water heaters should work during a power outage, since electricity is only used to spark the pilot light and is unneeded for the continual operation of the unit as long as the pilot light remains lit. Sometimes, however, your pilot light may keep going out and will need to be relit.

Does a gas furnace have emergency heat?

In most cases, emergency heat is electric, but it can also run on natural gas or oil. When you manually set the emergency heat on your thermostat, your system bypasses the heat pump and directly accesses either the electric heat strip or the gas or oil furnace.

How does an old gas heater work?

The gas is brought into the combustion chamber via gas jets. Then, a pilot light (in older furnaces) or a hot surface ignitor ignites the gas jets. The heat exchanger, which is a set of coils or looped metal where air passes over, is heated by the lit gas.

How much power does it take to run a gas furnace?

The average furnace is about 1000 watts, but this can vary depending on the size and type. The power consumption of your furnace will vary depending on its size and efficiency. A typical gas furnace will use between 30 and 60 amps of power, while an electric furnace will use between 50 and 100 amps.

How long will hot water last without power?

A water heater with a tank keeps a large reserve of heated water, but the water will only stay hot for so long. You may have an hour or two until that reserved hot water cools down. So yes, if you have a tank water heater and the power went out recently, you can probably still take a shower.

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