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Why Does My Furnace Smell Weird And Other Questions?

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Snuggling up with your fluffiest blanket after cranking up the heat on a cold night is one of the simple pleasures around this time of year. But when your mind is constantly wondering about the furnace’s strange smell and that weird noise it just made, it’s difficult to enjoy that cup of hot cocoa in your hands. 

Why does my furnace smell funky? Did my furnace always use to bang when it turned on? What is causing my furnace to leak water? Stop! The experts are here to answer all your questions, so let’s get off that anxiety spiral.

1) Why Does My Furnace Smell Strange?

There are many reasons why your furnace smells. So first, let’s identify. What is the smell exactly? Common odors are burning dust, rotten eggs, a musty odor, and car exhaust. 

When you first turn on the furnace for the heating season, it is normal to smell burning dust. Give it a few days to burn away the collected dust. If it still smells like burning dust after a couple of days, you may need to change your return filters and schedule a heating maintenance for cleaning. Here’s a tip: Replace your return filters every three months or more frequently if you have pets, carpeting, or household members with allergies. Below is an example of a filthy filter.

A musty furnace odor could mean that water has seeped into the unit. If this is the case, you should have a technician maintain your furnace so that they can check for any loose piping.

Ever walk past a sewer plate only to smell rotten eggs? That is hydrogen sulfide. This stench is frequently a sign of escaping sewer gas or a gas leak. If you smell rotten eggs coming from your furnace, please turn off the heat and call us immediately. 

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

2) Why Does My Furnace Keep Tripping the Breaker?

Your furnace trips the breaker whenever it is working super hard. We often find that dirty filters and a dirty furnace can cause the furnace to work harder, which then trips the breaker. Getting your furnace maintained once a year is an easy way to prevent this and other potential issues. The furnace may also have a malfunctioning part, which is making the furnace work harder and use more electricity.

This issue could also be from a short circuit within the furnace, or the breaker itself may be faulty. After ensuring your filters are clean, call us to schedule a maintenance visit if the breaker still trips.

3) Why Is My Furnace Blowing Out Cold Air?

First, ensure your thermostat is on heat mode if your furnace is blowing cold air. After that, check to see if the filters in your furnace are dirty. Here is a helpful tip: When you can no longer see light through your filter when you hold it up to the light, it is time to change it.

If, after checking,  you are still getting cold air from your furnace, you should have an HVAC service technician come out since the issue is most likely a sign of a faulty component. 

4) Why Does My Furnace Keep Turning Off?

If your furnace keeps shutting off, check the thermostat and change any filthy filters—dirty filters can force the heater to work harder.

Again, after checking the thermostat and filters, if your furnace is still turning off, call an HVAC service technician to come out.

5) Why Is My Furnace Banging?

If your furnace makes a banging sound when it first turns on, it may indicate that the burners are dirty. Filthy burners allow gas to accumulate before igniting, which causes it to explode with a loud bang when it eventually ignites. By having routine maintenance done on your furnace, you can easily avoid this jump scare. 

When you hear popping sounds, the heat is causing your ductwork to expand and contract. You’ll hear this more frequently if your vents are closed, or your filters are dirty.

6) What’s Causing My Furnace to Leak Water?

The most likely cause of a furnace’s water leak is a clogged condensate line. Leaking water can also be a symptom of a cracked heat exchanger, which is extremely dangerous. If you’re concerned that your heat exchanger might be the problem, read this article about the signs of a cracked heat exchanger.

It is an excellent habit to always check your thermostat and filters whenever your HVAC is acting strange, whether it is blowing cold air or the furnace smells. If your furnace is still not working correctly or you are worried about it, click here to schedule an appointment with us. 

Many problems can be avoided by having your HVAC system maintained twice a year, once in the spring or summer for your air conditioning system and once in the fall or winter for your furnace. This biannual maintenance is included in our Comfort Club Maintenance Program, which provides priority scheduling, discounted emergency service, extended warranties, and a 15% discount on repairs and select indoor air quality items.

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