Why Does My Furnace Smell and Other Questions

Wrapping yourself up in a blanket after you’ve turned up the heat on a cold winter’s night is one of the many simple pleasures found this time of year. However, it’s hard to truly relax when your mind keeps wondering if it’s normal for a furnace to smell funky.

Why does my furnace smell? Does that banging noise from the furnace mean it’s working or is something wrong? Why is there water leaking from my furnace? Stop! You don’t need to go down that anxiety spiral because we are here to answer all your furnace questions and help ease your mind.

1) Why Does My Furnace Smell?

Smells coming from the furnace can be a result of many different things. Some common smells are burning dust, rotten eggs, car exhaust, and a musty smell. 

If you smell burning dust when you first turn on the furnace for the heating season, allow it to burn away the accumulated dust for a few days. If your furnace smells like burning dust after a few days, it could indicate that you need your furnace maintained or you need to replace your return filters. Return filters should be changed every three months or more frequently if you have carpeting, pets, or allergies. Below is a picture of what a very dirty filter looks like.

A musty furnace smell could indicate that water has gotten into your furnace and that you need to get your furnace maintained so a technician can check to ensure there isn’t loose piping. 

The smell of rotten eggs comes from hydrogen sulfide. This smell often indicates a gas leak or escaping sewer gas. If you smell this coming from your furnace, please turn off your heat and contact us immediately. 

Similarly, if your furnace smells like car exhaust or gas or you don’t smell anything, but your CO detector is going off, please turn off the heat and request emergency service. 

2) Why Does My Furnace Keep Tripping the Breaker?

Most commonly, your furnace filter or the furnace itself may be dirty, which causes it to work harder. Having your furnace maintained annually is a great way to prevent this and other issues that may occur. The furnace may also have a faulty component, causing it to work harder and again draw too much power. 

Your furnace may also be tripping the breaker because the breaker itself is faulty, or you may have a short circuit within the furnace wiring. Whatever the cause may be, first check that you have clean furnace filters. If the breaker keeps tripping after you’ve checked that your filters are clean, call to book an appointment. 

3) Why Is My Furnace Blowing Cold Air?

If your furnace is blowing cold air, you first need to check your thermostat and make sure that it’s set to heat mode. Afterward, you need to check your furnace’s filters to make sure that they are not too dirty. It’s time to replace your filter when you can’t see light through it.

If your furnace is still blowing cold air after you’ve checked your thermostat and filters, have an HVAC service technician come out and help you since the issue is most likely caused by a faulty component in the furnace. 

4) Why Does My Furnace Keep Turning Off?

Check the thermostat and replace any dirty filters if your furnace keeps turning off, as dirty filters can make the furnace work harder.  

Again, if your furnace is still turning off after you’ve checked the thermostat and filters, have an HVAC service technician come out. 

5) Why Is My Furnace Making a Banging Noise?

If your furnace makes a banging noise when it starts up, it could indicate that the burners are dirty, which causes gas to build up before it ignites. When it finally ignites, it makes a banging noise. You can easily avoid this issue by having your furnace maintained regularly.

If you hear popping noises, it is most likely your ductwork expanding and contracting because of the heat. You’ll hear it more often when your filters are dirty or if your vents are closed.  

6) Why Is There Water Leaking from My Furnace?

The water leaking from your furnace is mostly likely from a clogged condensate line. However, cracked heat exchangers, which are dangerous, can also cause leaking water. Check out this article about cracked heat exchanger symptoms if you are worried your heat exchanger may be the cause.

It is good practice to check the thermostat and filters first whenever you find your HVAC system is not working or if you find your furnace smells or is making a banging noise. If your furnace is still not working properly or you are worried about how it is running, schedule an appointment immediately.

Having your HVAC maintained biannually, once during the spring or summer for your AC system and once during the fall or winter for your furnace system, can prevent many of these issues from happening in the first place. Our Comfort Club Maintenance Program offers this biannual maintenance along with a 15% discount on repairs and select indoor air quality products, priority scheduling, discounted emergency service, and extended warranties.    

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