5 Common Gas Furnace Problems and Solutions

Nothing ruins your night like waking up from a blissful sleep in the middle of a chilly winter night because your gas furnace is not working poorly. Many people tend to get surprised when they find their gas furnace functioning poorly once they start using it in the fall or winter.

However, it’s a common problem, and the solution isn’t always complicated. A problem with your furnace that may seem difficult to fix oftentimes just needs a simple fix. So, with a little DIY experience, you can troubleshoot and fix your furnace yourself without calling for professional help.

In this article, we’ll be helping you find solutions to the 5 Most Common Gas Furnace Problems.

Problem 1: Thermostat Is Switched Off

This may seem like an uncommon problem. However, it’s the opposite. Many service calls are made because the thermostat on peoples’ furnace is switched off, or if they’re aware of the problem, many people don’t know how to turn on the thermostat on their furnace.


Step 1:

If your home’s thermostat unit runs on batteries, make sure you change these batteries once every year. In some cases, changing the batteries on your thermostat may fix the problem especially if it frequently switches off.

Step 2:

If that fails to work, make sure to check that no debris or dust is clogging the thermostat. If you spot any, that may be the problem. Blowing the dust or debris away may solve the problem.

Step 3:

Another thing to be wary of is the electronic models. Sometimes, the system tends to go on timer mode, causing your furnace to frequently switch on and off. Make sure to set the correct date and time on the electronic models.

Problem 2: Furnace Is Not Producing Enough Heat

Sometimes, your furnace may be working, but the heat is not enough to keep the whole house warm. This can be due to clogged airflow due to a dirty furnace air filter or unmaintained air burners.

When air filters are clogged, they don't only affect your furnace's ability to produce heat but can also result in increased utility bills as it causes your air handler to work harder to make up for the blockage in airflow.


In this case, the first thing to do is make sure your air filters are clean and in fairly good condition. If you haven't replaced an air filter on your furnace in a long time, now may be the right time to do so. This will cause the air to flow through smoothly again and should fix the heating problem of your furnace.

If that fails to work, call a professional technician to clean or adjust the burners. This will ensure the airflow to the combustion air chamber isn’t blocked and will fix the problem.

Problem 3: Furnace Leaking Gas


Gas Furnace is great at keeping you warm. But like all other appliances, they come with their risks. Gas leaking from your furnace can cause a sulfur-like smell that resembles the smell of rotten eggs to release around the house.

This is most commonly caused by a cracked heat exchanger. Gas leaks can cause harmful chemicals to release around the house and require your immediate attention due to the dangers associated with them.


Gas furnace leaks pose serious health and safety risks. However, they can be prevented. If you suspect a gas leak, it's best to call a registered gas safe registered engineer to inspect all gas appliances in your house.

It's also essential to know that in the UK, you're required by law to have a registered engineer inspect the gas appliances in your home and obtain a gas safety certificate.

Moreover, make sure to immediately shut your HVAC system off, open doors and windows to ventilate the house, avoid lighting any matches or candles, and exit your house.

Problem 4: Your Furnace Is Too Noisy

A noisy furnace is not annoying but it can also indicate a problem with the overall operation of your furnace. However, lucky for you, sometimes the cause of the problem can be fairly innocent that you can easily fix by yourself.

Although the cause and solution of the problem usually depend on the kind of sound the furnace is making, we've picked up some of the most common noises your furnace can make and their solutions:


If your furnace is producing a squealing sound, it is most commonly caused by a loose or unadjusted fan belt or a lack of lubricant. In this case, try applying oil or tighten the blower belt to stop the noise.

If your furnace is producing a vibrating noise that may also resemble a thumping sound, this means the blower wheel on your furnace is unbalanced. In this case, you’ll need to call for professional help as an unbalance blower wheel can damage your furnace.

Problem 5: Furnace Fan/Blower Always Running


The blower on your furnace should only run when your furnace is in the middle of its heating cycle. If it tends to run continuously, it’s an indicator of a problem.


Step 1:

In this case, the first thing to do is check your thermostat settings to ensure its set correctly. Set the thermostat temperature to a lower temperature. This shuts down your furnace and prevents the thermostat from requiring more heat. This may cause the blower from running continuously.

Step 2:

Another thing to recheck in this case is the auto/on setting on your furnace fan. Make sure the fan is set on auto and not on as that will cause it to run non-stop.


Sometimes, troubleshooting and repairing your gas furnace you will save you time and extra expenses as not every problem requires professional help. We hope you find the solutions to the 5 most common gas furnace problems helpful!


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