Will A Gas Furnace Work Without Electricity?

A gas furnace is an excellent choice for a reliable heating source. But what happens when the power goes out? Can a gas furnace still work without electricity? 

Even though they are known as gas furnaces, modern units will not work without electricity. That is because a modern gas furnace is made of several components that use electricity to help it function as heating equipment. However, it may still work if the furnace has a standing pilot light and no electronic controls.

Whether you’re a homeowner, renter, or building manager, this guide will help you understand how your heating system works and how to stay warm and safe during a power outage.

Why Will a Modern Gas Furnace Not Work Without electricity?

You may be wondering why a gas furnace would still need to use electricity to work, but here is the thing, gas furnaces are made up of different components that require electricity to function.  These include safety features and the circuit control boards acting as your furnace’s brain.

Parts of a modern furnace that use electricity

Even though gas furnaces use the burning of gas to produce heat, a furnace comprises components such as those outlined below.

  • Circuit control board: The circuit control board is the motherboard of a furnace. It has different circuits and fuses, and the primary function of this component is to receive instructions from the thermostat, which are then sent to other components of your furnace system. 

To carry out its function, it requires electricity. Because even from the furnace to ignite, instructions must be sent from the circuit control board to the ignitor.

  • Thermostat: While some thermostats are equipped with batteries, many other thermostats depend on the 24 volts from the furnace. The primary function of the thermostat is to adjust the temperature.  When there is no electricity, your thermostat will not even be able to turn on the furnace.
  • Blower motor: This is another important component of the furnace that will require electricity. The blower’s function is to blow the heated air into the duct system to reach the intended spaces. The heated air will not move an inch when the blower is not powered up.
  • Ignition system: The ignition system is responsible for lighting up the flames on the burners. Components that make up the ignition system include the hot surface ignitor and the flame sensor. All these parts need electricity for the furnace to ignite, including the wall switch.

Returning to modern furnaces, they will all need electricity to function, gas, and electric furnaces.

While gas furnaces need electricity to operate, they still differ from electric furnaces because they use burned gas for heating. In contrast, electric furnaces use electrical elements( by electrical resistance) to heat the air.

The two types can be confusing sometimes but below is a table outlining the differences between gas and electric furnaces.

FeatureElectric FurnaceGas Furnace
Fuel sourceElectricityNatural gas or propane
Cost to operateTypically more expensiveTypically less expensive
Environmental impactEmits no carbon monoxide or other harmful gasesEmits carbon monoxide and other harmful gases
MaintenanceRequires less maintenanceRequires more maintenance, such as annual inspections and cleaning
Initial costTypically less expensiveTypically more expensive
LocationCan be installed anywhereMay requires access to a gas line

What to do when a gas furnace stops working after a power outage

If your gas furnace does not work after an outage, do not panic, there are a few troubleshooting steps you can take to restore your furnace.

You first want to ensure that your thermostat is set to heating mode and that the temperature is raised above the current room temperature. If the thermostat setting is not an issue, you might want to look at the circuit breaker.

It is not uncommon for breakers to trip during power outages. Check and reset switches where necessary.

If it’s still not working after you have checked the thermostat and the electrical circuit breakers box, your furnace may need a reset.

Head over to the furnace and locate the reset switch. The reset switch is typically red or yellow. Try pressing it to reset it and get your furnace back to running. If this doesn’t fix your furnace, consider calling a licensed HVAC professional to come and take a look. Find HVAC professionals in your area now by calling 1-877-342-2087

How to turn on a gas furnace without electricity?

A gas furnace requires electricity to power the fan and control systems, so it cannot be turned on without electricity. If the power is out and you need to use the furnace for heat, you may consider using an alternative heating source such as a fireplace, wood stove, or portable heater. Some newer furnaces come with a battery backup system that will allow them to run for a short period of time in the event of a power outage, so you can check your furnace manual or contact the manufacturer to see if this option is available.

Old school furnaces, however, would work without electricity. Let’s briefly look at these furnaces to appreciate better how modern furnaces work.

Furnaces that Work Without Electricity

Talking of older furnaces was widely known as the Octopus furnaces. These ( in the photo above)  did not need electricity but still functioned as full central heating systems.

 These furnaces were more common in the early days from about the 1940s and were very expensive to install and maintain.

The Octopus furnaces used oils and coal for heating, relying on the principle that hot air rises above. They were installed with pipes and lines resembling octopuses called Octopus furnaces.

So, in general, the octopus furnaces are long gone, dead, and buried. Unless you are ‘an old house’ type of person, you may still have some luck and find homes that are still using them. 

That leaves you a few options for furnaces to use when the power is out.

Alternatives to Furnaces During a Power Outage

Despite furnaces’ limited functionality during a power outage, there are still a few things you can consider if you need something to keep your space warm without requiring power from the utility grid. These include investing in a propane or paraffin heater, in which both cases don’t require electricity to work.

Mr Heater 4000 to 18000 BTU 3 Setting Portable LP Gas Heater Unit with Dual Tank Connection for Indoor and Outdoor Use, Black/Red
  • Propane Tank Heater: Heat up your camping or picnic area, porch, shed, and more with a handy propane heater with variable settings for custom warmth anytime, anywhere you bring it
  • Heat Levels: Gives off 4,000, 9,000, or 18,000 BTU per hour with a 450-square feet heat range and can be used with propane tanks up to 40 lbs with the use of an additional hose and filter
  • Simple Usage: Single control start knob allows easy usage with a piezo sparking mechanism for reliability with automatic safety shutoff in case the patio heater tips over
  • Possible Connections: Can connect to a pair of 1 lb propane tanks with 2 swivel regulators for a remote gas supply for your outdoor heater; Hose, filter, batteries, and propane are not included
  • Possible Connections: Can connect to a pair of 1 lb propane tanks with 2 swivel regulators for a remote gas supply for your outdoor heater; Hose, filter, batteries, and propane are not included

Investing in a Genset, a portable or stationary device that generates electrical power using an internal combustion engine or a turbine, would be the best option to extend the central heating system beyond power outages.

The power generated by portable batteries is typically used as a backup power source or in remote locations where utility power is not available. Gensets can be powered by various types of fuels, including diesel, natural gas, and propane.

Jackery Portable Power Station Explorer 300, 293Wh Backup Lithium Battery, 110V/300W Pure Sine Wave AC Outlet, Solar Generator for Outdoors Camping Travel Hunting Blackout (Solar Panel Optional)
  • SPEED UP YOUR RECHARGEABILITY: It takes only 2 hours to recharge 80% battery of the power station through the wall outlet and 60W PD USB-C port simultaneously. You can also recharge your power station with an AC adapator when at home, through the car outlet during a road trip or simply use a Jackery SolarSaga 100.
  • SAFE & STEADY POWER SUPPLY: Armed with a 293Wh lithium-ion battery pack, the Explorer 300 features 2 Pure Sine Wave AC outlets that deliver stable and safe 300W power. The portable power station weighs only 7.1 pounds. You can simply rest assured in outdoor off-grid activities.

There are a few types of furnaces that can work without electricity:

  1. Gravity Furnace: These are older furnaces that use natural convection to circulate heat throughout the home. They do not have a blower motor and do not require electricity.
  2. Kerosene Furnace: These types of furnaces use kerosene as a fuel source and do not require electricity to operate.
  3. Wood-burning Furnace: A wood-burning furnace uses wood as a fuel source and does not require electricity to operate.
  4. Oil furnace with a Standing Pilot Light: Some oil furnace have a standing pilot light that stays lit all the time, which allows the furnace to ignite the burners without electricity.

It’s worth noting that these types of furnaces are not very common in modern households.

How to keep your space warm without electricity?

Use fireplaces: If you have a fireplace, use it to generate heat. You can even use traditional wood fireplaces to keep your space warm without electricity.

Use candles: candles can generate a surprising amount of heat. Light up a few candles and place them where you spend much of your time. It would be best if you kept an eye on candles, though, as they can be dangerous for kids and pets.

Use a wood stove: A wood stove can heat a room. Be sure to follow all safety instructions when using a wood stove.

Use a gas stove: If you have a gas stove, you can use it to heat a room by lighting up the flames of your oven and leaving it open.

Use body heat: Cuddle up with blankets and blankets to stay warm. This can be effective if you are a couple or you have a group of kids.

Use a portable heater: As I mentioned earlier in this guide,  if you have a portable heater, such as a propane heater, you can use it to heat a small space. Just be sure to follow all safety instructions when using a portable heater.

Use insulation: Proper insulation can help keep the heat inside your home. Check your insulation and consider adding more if needed.


Do I need to turn off gas when power goes out?

It is not necessary to turn off the gas supply to your furnace when the power goes out. The gas valve that supplies fuel to the furnace is typically not affected by a power outage and will continue to function normally. However, if you are concerned about the safety of your furnace during a power outage, you may want to turn off the gas supply to the furnace as a precautionary measure. It is important to note that some newer furnace models have safety systems that will shut off the gas automatically in the event of a power outage, so you should check your furnace manual or contact the manufacturer to see if this is the case with your furnace.

Can I run my gas furnace with a generator?

It is possible to run a gas furnace with a generator, but there are a few things to consider before doing so.

  • First, ensure the generator is rated to handle the electrical load required to run the furnace. The furnace’s fan and control systems require a significant amount of power, so you’ll need to ensure that the generator can supply enough power to run the furnace without overloading the generator.
  • Second, it is important to ensure that the generator is properly grounded and connected to the furnace’s electrical system to avoid potential electrical hazards.
  • Third, you will need to ensure that the generator is connected to a transfer switch that will allow you to switch between the generator and utility power safely.
  • Finally, you should be aware that running a gas furnace with a generator for an extended period of time can be pretty costly and may not be the most efficient way to heat your home, especially if you have a large home.

It is always best to consult with a professional electrician or HVAC technician to ensure that your generator is properly wired and connected to your furnace, and that it is safe to use.

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