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Musty Furnace Smell

Why Is My Furnace Making My House Smell?

Why Is My Furnace Making My House Smell? 

Your furnace is prone to making a smell every now and then. Most furnaces will have a slight burning smell when they first start for the winter. This is the result of excessive dust burning off of your system's components. While this smell is completely normal, there are some other common smells that aren't.

Metallic Smell

A very distinguishable smell that your furnace may emit is a metallic one. This is a clear sign that an internal component of your heating system is overheating. This can be burning rubber, plastic, or oil. In this situation, it's best to shut off your furnace and contact an HVAC professional right away. If you notice smoke or fire, be sure to contact your local fire department for help.

Rotten Eggs

Another very distinguishable smell is that of rotten eggs. This potent smell alerts you of a gas leak. This smell will only occur in systems that run on natural gas. The gas company adds a rotten egg smell to their gas so that you can mean when you have a leak. When you smell this noise, you need to shut off your gas valve and contact your utility company right away. Gas leaks can be very dangerous and even fatal in some instances.

Musty Odor

One odor that can be quite alarming is that of a mustiness. This smell can mean that there is mold or mildew present somewhere in your ducting. You can fix this issue by having your ductwork cleaned by an HVAC expert. You should never let mold or mildew smells go on. The spores they create will enter the air inside of your home. This can result in respiratory issues for your family members.

Chemical Odor

Another very distinctive odor that your furnace may emit is that of a chemical basis. Most consider this smell to be like formaldehyde. This chemical odor can mean that there is a crack in your heat exchanger. This can allow toxic fumes like carbon monoxide to seep out into your home. It's best to turn off your system immediately and have an HVAC pro assess your system for damage.


You never want to smell a smoke odor coming from your furnace. When this happens, it's likely a result of a blockage in your exhaust pipe. When your furnace combusts fuel, the smoke should enter into an exhaust pipe that vents the odor out. When there is a blockage, those toxic fumes enter back into your ducting and throughout your home. This is very dangerous. Open your windows, shut off your furnace, and get a professional to your home right away.

Call Us Today

If you're experiencing any unusual odors coming from your furnace, then it's time to give us a call today. Let our helpful HVAC professionals check out the smell. We can provide you with a quick fix to remedy the odor and get your furnace back in good working condition.