8 Smells a Furnace Can Produce and How You Can Fix Them


A furnace is a must-have for any home, primarily because it will be extensively used during the winter months. While it produces heat, it’s not always perfect because it can experience problems now and then. One such example is when it produces smells that it shouldn’t.

There are many reasons why a furnace would produce smells out of the ordinary. Sometimes the smell is simply a result of the heating system used in the home. More often than not, the scent results from a problem with the furnace that needs to be addressed. Regardless, it shouldn’t be producing any smell at all, and you should get it fixed as soon as possible.

This article lists some of the most common smells that a furnace shouldn’t produce and what you can do to fix them. Read on below to get started.

#1 – Smoke

There’s a good chance that you will be able to detect a small amount of smoke if it’s coming from your furnace. Smells like this are not something you should be looking for in any case.

Depending on the cause of the smoke, the problem may be easily fixed by changing the filters and ensuring that all soot is cleaned from the gas burner, flame tube, and heat exchanger. On the other hand, if the cause of the smoke is a result of a failed motor, you should call in a professional to fix it.

#2 – Burning Dust

If you’re smelling something that feels like burning dust, it’s usually a result of overheating. This can be because of a faulty motor or perhaps a clogged filter.

The easiest way to rectify this is to get the air filter cleaned. Still, you also need to check your furnace to ensure that dust is not being sucked into it.

#3 – Rotten Eggs

The smell of rotten eggs is usually a result of gases being released from the gas burner. This smell commonly happens when the gas valve is turned off, but it shouldn’t be a problem in the first place.

The smell can be fixed by checking the gas valve and burner assembly. If the problem persists, you should call a professional.

#4 – Foul Sewage

Many factors can cause a foul sewage smell or something similar to it. It can result from a blocked drain line, a problem with the pump, a broken gas safety shutoff, a clogged filter, and many more.

The smell can be fixed by cleaning the drain line in most cases. On the other hand, if the smell persists and the problem is not something as simple as a clogged drain, you should call a technician to fix the problem.

#5 – Your Pet’s Smell

If you have an animal at home that’s shedding hair, this can contribute to the smell of your home. Some people also keep pets in areas where the furnace is kept. If that’s the case, there may be a chance that the smell is coming from your pet.

If you have noticed your pet’s smell coming from your furnace, you should remove the pet from the area. You should also clean the filter and ensure that the motor is free of dust. You may also consider switching to an air purifier if the problem persists. The purifier will help remove the pet’s hair from the air.

#6 – Mold

Mold is a problem that needs to be addressed quickly. The smell it produces is one of the first signs of mold growth. Even though you may not see the mold, it’s a good idea to call a professional to inspect the heating system and make sure that mold isn’t growing anywhere in it.

The mold may be growing on the vent or in the ducts. More often than not, the mold results from the heating system being kept in an area that’s too moist. You should ensure that the area stays dry to avoid mold growth.

#7 – Scent of Metal

If there’s a scent of metal coming from your furnace, there’s likely a problem with your motor. A bad motor can cause this problem. If it’s not, it could be caused by something else.

The problem with a bad motor is that it can cause an overload and burn out. A refrigerant leak can cause this. The smell of the burning refrigerant can cause a burning smell. In this case, it’s recommended that you call a professional to fix the problem for you.

#8 – Chemicals

If you notice a chemical smell coming from your furnace, it can be caused by gas. The scent can be easily detected because cracks and pops usually accompany it. The scent can also be detected if you hear a knocking noise.

The smell is usually a result of a gas leak in the system or a clogged orifice. To fix the problem, you should open up the furnace. If there’s a leak, you should resolve the problem by replacing the faulty parts.


The smell coming from the heating system of your home can be quite off-putting, especially if it’s not something you’re used to. It’s recommended that you take care of the problem as soon as possible. If you’re not able to identify the source of the smell, you should call a professional.

Mainline Heating and Air provides top-quality services for heating and cooling repair in Alabaster, AL. Our team of experienced professionals can fix any problem your HVAC system could have, all for an affordable price. Contact us today to learn more!

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