Why Furnace Smells Like Its Burning!

There are many reasons your furnace may smell like its burning – some simple, but some may need the attention of a qualified HVAC technician.

You can take the first steps in determining what the odor is and if it may be something that needs to be checked out.

Always consider burning smells that emit from your furnace to be of danger and you should check them out immediately.  If you smell gas, contact your gas company immediately!

First start up of the Season

We have all smelled it, that icky smell that circulates through your home when you start your furnace for the first time of the season.  It usually lasts less than an hour and smells like dust burning – which is exactly what it is. The best way to minimize the smell is to change your furnace filter and dust off the furnace and grill before turning it on.  This will cut down on the amount of dust and debris available to burn and chances are, you will only smell it for 5-10 minutes.

Clogged or Dirty Filter

If you haven’t changed your furnace filter and it is clogged with dust and dirt, this is probably the culprit.  Follow our instructions for Changing Your Furnace Filter, restart your furnace and see if the smell is gone.

Duct Cleaning

Having the ducts cleaned is not something that most of us do very often – unless we have a maintenance contract with an HVAC contractor.  If you have a constant burning smell and you have changed the filter and checked for excess dirt and debris, you should probably call a professional about having the ducts professional cleaned.

High Resistance

In our quest to save money, we sometimes close off registers in rooms of our homes that are not often used.  While doing so is perfectly fine, if you close more than 20of the registers in your home, it can cause high resistance and heat to build up in your furnace – wherein, a smell of smoke may be emitted.

Clean the Burners

If the burners in your furnace are caked with dirt, they are likely to emit a smokey smell.  Make sure you turn off your furnace and before you clean the burners.  You can also follow the instructions for Inspecting Your Furnace.

Overheating Motor

If the motor on your furnace is going bad, it could definitely smell like smoke.  Some furnaces have motors that need to be lubricated at least once a year.  If your motor needs to be lubricated, turn off the system and apply 2-3 drops of 10 weight nondetergent motor oil to each port. Do not put too much oil on it!.  Restart the system and see if the smell goes away within 15-30 minutes. You can purchase the oil at most hardware and home improvement stores.

Cracked Heat Exchanger

Most likely, this will not be the problem (because you would smell gas instead of smoke), but if you have done everything else above, then I would suggest you contact a qualified technician to find out what the problem is.  A cracked heat exchanger is the single most dangerous thing that can happen to your furnace, so you need to have it checked out immediately.

There are many ways to rule out the reasons you may be smelling smoke from your furnace, and in reality, the most common reason is that the filter is dirty.  Completing a furnace inspection twice a year can help you maintain your system a little better and keep costly repairs to a minimum.

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One Response to “Why Furnace Smells Like Its Burning!”
  1. mike belanger says:

    my friends has a newly installed gas furnace and new ducting, but is experiencing an odor problem. The installers are at a loss.