Category - Boilers
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Will Scholfield, Engineer

31 Jan : Updated 17 Apr ● 5 min read

Does gas central heating work in a power cut?

Power cuts are the worst! And it's safe to assume that a gas central heating system will work during a power outage since it works on gas and not electricity, right? Actually, no; most gas boiler heating systems have certain parts that rely on electricity for their overall functioning.

But it also depends on your system; some gas systems may work, while others won't. We're here to tell you what you can and should do in the case of a power cut.

The Parts Of A Gas Heater That Need Electricity

Even though a gas heater relies on gas to generate heat, it may also depend on various other parts that need a power supply to work efficiently and effectively. These are some of the components that certain gas heaters may have that require power:


When it comes to the thermostat, there are some exceptions. But most rely on a source of electricity to communicate and calibrate with the central heating system. For a more detailed explanation of how a central heating thermostat works, check out our comprehensive guide.

Circuit boards and relays:

Most modern gas heating systems have relays, circuit boards, and various other components that cannot function without electricity.

Types Of Gas Heating Systems:

Electric ignition controlled:

This type of heating system needs electricity in order to ignite the gas burner, so an electric ignition-controlled heating system will not work during a power cut.

The water that is already in the tank may stay warm for some time, but any new water coming into the tank will not get heated as it will need power so it can reheat all of the water inside the tank.

An electric ignition-controlled system requires a high-voltage spark to light the furnace's burners. There are two different types of systems:

Intermittent pilot light

This system has a pilot light, but an electrical spark is required to ignite the light. The pilot stays on for long enough to turn the burners on, and then it turns off.

Hot surface ignition

This system works via an electrical current that flows through the filaments; it heats them via electrical resistance heating. This heat then lights all of the burners.

Both types of systems require some form of electrical current to work, so they won't be able to function during a power cut.

Pilot light controlled:

This type of heating system will run like normal during a power cut as it does not rely on an electrical supply to function. Systems that use a pilot light are not as common anymore as modern heating systems have evolved.

However, some may still have this type of system at home. The pilot light can be found inside the furnace, and it is a flame that remains lit in order to ignite all of the burners when gas starts flowing from them.

The pilot light uses the natural gas that comes from the furnace to remain lit, so this type of heating system will work perfectly fine during a power outage, as the pilot light is what ignites the burners, not electricity.

If you have this type of system, it is likely very old and is due to be phased out very soon. As this is the case, finding a new boiler and replacing it would be best. Luckily, BOXT has a wide range of modern central heating systems to choose from!

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When The Power Goes Out:

Most homeowners with a gas central heating system will, unfortunately, be without heat during a power cut as the system will not work without an electrical supply. Unless they have a heating system that is pilot light controlled!

It won't work because the furnace has a safety system that automatically kicks in and won't allow the furnace to turn on in the middle of a power cut.

It can be very frustrating not having heat but do not fiddle with the furnace and try to get it to work during a power outage - this can compromise your overall health and safety.

If you are very worried about power outages and not having a functioning heating system, you could consider calling a qualified electrician and HVAC service technician to come in and connect your furnace to a suitable generator. The generator will give power to all of the components that rely on electricity, and this way, you will have a fully functioning central heating system during a power cut. Only get a certified, experienced, and licensed team to do this for you!

What You Should Do:

In the case of a power cut, unfortunately there isn't much you can do apart from wait for the electricity to come back on! 

Once you have power back again, check if your boiler is showing any fault codes and if it is, try resetting it to clear the error. You should also check whether the power cut has impacted the time and schedule set on your thermostat, and reset these if needed. 

So, Will It Work?

It depends on the type of central heating system you have. The answer is yes if you have a pilot light-controlled system, as it relies solely on gas and a flame to heat up.

But if you have an electric ignition-controlled system, then the answer is no. This is because various components rely on electricity to function correctly, and an electrical current is needed to ignite the burner.

Always check your circuit board for tripped switches and your fuse box before doing anything else, as it may just be an issue in your home, not a power cut. Either way, if you’re wondering whether you should switch your boiler type, check out our guide to electric boilers vs gas boilers to help you decide which is right for you.

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