Abdul Hameed Dec 05, 2022

What Causes Odors in Your Furnace? The Meaning of 5 Strange Furnace Smells

Have you ever wondered, “What is that weird smell coming from my furnace?”. Furnace odors can be strange and mysterious, but they usually indicate an issue that needs to be addressed with your furnace. If you notice odors emanating from your furnace, please get in touch with us to schedule a furnace repair. Our certified HVAC technicians will ensure it gets fixed ASAP. We provide furnace repair services throughout Phoenix, Arizona, and the surrounding areas.

Here are some of the most common causes of odors in furnaces:

  • One of the most common causes of furnace odors is a build-up of dust and dirt on the components. Over time, this build-up can cause the furnace to overheat and produce an unpleasant smell. To prevent this from happening, it’s important to regularly clean your furnace and change the air filters.
  • Another common cause of furnace odors is a problem with the furnace’s venting system. If the vents are blocked or not working properly, odors can escape into the home. You’ll need to schedule a professional inspection and repair the venting system to fix this problem.
  • Finally, furnace odors can also be caused by leaks in the furnace itself. These leaks can allow dangerous gasses to escape, which can affect your health. If you suspect a leak, it’s important to have one of our professionals inspect and repair the furnace as soon as possible.

There are different meanings for various odors emitted from a furnace. Here are some of the most common reasons for odors produced by the furnace that indicate the need for repair:

  1. Burning Plastic or Rubber: If you smell burning plastic or rubber, something in your furnace is likely overheating. This could be a sign of an electrical issue, so it’s important to call one of our furnace repair technicians right away.
  2. Ammonia: Ammonia smells like a strong chemical odor. If you notice this smell coming from your furnace, there is likely a problem with the furnace’s heat exchanger. This serious problem should be addressed as soon as possible by one of our trained furnace repair technicians.
  3. Rotten Eggs: If your furnace smells like rotten eggs, there is likely a problem with the furnace’s gas line. This serious issue can be dangerous, so it’s essential to call a furnace repair professional immediately.
  4. Mold or Mildew: If your furnace smells like mold or mildew, there is likely a problem with the furnace’s air filter. This is a relatively easy problem to fix, but it’s still important to get a well-experienced technician to inspect the unit and have the filter replaced. LJ Refrigeration Co., Inc is here to help and assist with any issues you may be experiencing.
  5. Burning Dust: If your furnace smells like burning dust, there is likely a problem with the furnace’s blower motor. If you are facing this issue, call us and let us fix your problem by replacing the motor so that you no longer have to face any inconvenience.


The odors mentioned above usually indicate a serious problem that needs to be addressed quickly and efficiently. Call us at (480) 948-5004 for heating services in Phoenix, AZ, if you notice any strange furnace smells. Our experienced technicians will immediately assist, as LJ Refrigeration Co., Inc. is one of Phoenix’s most experienced and reliable HVAC companies.