What is That Odor From the Furnace?

When the weather cools and you turn your furnace on for the first time, you’re probably aware of a burning smell. In general, that’s just dust that has accumulated in the heat exchanger over the months since you last used the furnace. The dust burns off quickly so that after a few minutes to an hour or so, the furnace smell should have dissipated.

But your furnace may be emitting other smells, and some of them may be of concern. Here’s a short roundup describing some of the most common furnace odors.

Musty, Moldy Smell

Most often, a musty smell emanates from the air conditioner, but it may also be present when the furnace is on. It could be damp dust, but it may also signal the presence of mold or mildew. Mold gets a footing in your HVAC system whenever damp conditions prevail. Mold may be growing in the condensate drain, around the evaporator coils, wherever water might be leaking inside the HVAC cabinet, or in the ductwork and vents.

You will probably have to hire an HVAC tech to inspect your system and clean it out.

Another possible cause could be a dirty filter, which can collect moisture and spawn mold and moisture problems.

Rotten Egg Smell

This should never be ignored, as it may be a gas leak. Open windows, round up all human and animal inhabitants and vacate the house. Call the gas company. Your utility will have to give the all clear before an HVAC tech can work in the house.

Electrical or Metallic Smells

This type of smell usually happens from furnace components getting too hot. If, along with the burning electrical smell, the furnace shuts down, it could be prompted by a safety mechanism. Call for a technician right away.

Other burning smells might indicate either metallic or rubber parts are burning up, as can happen with old age and general wear. Shut down the system and call for repair.

To learn more about how to deal with a furnace smell, contact Rinaldi’s Energy Solutions. We’ve served Orlando since 1969.
Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems).

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