Six Different Furnace Smells Decoded

Girl holding her nose

It is not unusual for a furnace to produce an odd smell when you turn it on for the first time of the season. But if you have been running your furnace a while and you begin smelling something foul emitting from the duct or the furnace equipment itself, it may be a sign of trouble. Some smells can be prevented with consistent furnace maintenance, but more serious issues like a gas leak could require more extensive service like furnace installation, especially if the smell is ignored for too long.

Below are seven smells your furnace may produce and what that smell could be an indication of. When you’re ready for professional service to resolve the odor, give Simons Heating & Cooling a call at 518-535-1870.

1. Furnace Smells Like Burning Hair

The smell of burning hair from a furnace can indicate a potential electrical issue or a problem with the furnace’s blower or motor. If the furnace’s blower belt is frayed or slipping, the belt may be rubbing against the motor or housing, producing a burning smell. Dust and debris can also accumulate on the heating elements, which can cause a burning hair odor.

Resolving the odor can often be as simple as cleaning the heating element, but to safely address the issue, it’s recommended to have a professional HVAC technician like Simons inspect the furnace to prevent potential hazards from damaged electrical systems.

2. Furnace Smells Like Gas or Rotten Eggs

The smell of rotten eggs often means there’s a potential gas leak. Natural gas is odorless on its own, so a strong, sulfurous odor is added to help detect these dangerous leaks. If you smell a rotten egg odor coming from your furnace, it’s crucial to evacuate the home immediately and call the gas company and emergency services to report the issue.

Do not use any electrical switches, appliances or ignite any flames, as this could cause a spark that ignites the gas. A gas leak can be very dangerous, so it’s important to take immediate precautions and have a professional resolve the issue.

3. Furnace Smells Like Sewage

If your furnace smells like sewage, it could be due to a clogged or backed up drain line. The drain line is meant to remove condensation from the furnace, but if it becomes clogged, the water can overflow and create a sewage-like odor. It’s recommended to turn off the furnace and call a professional to resolve the issue. In some cases, it may also indicate a more serious problem involving your plumbing system. 

4. Furnace Smells Like a Dead Animal

If your furnace smells like a dead animal, it’s possible that it IS a dead animal (like a squirrel, mouse or rat). Unfortunately, something may have crawled into the furnace and gotten trapped. This can happen if there are gaps in the furnace that provide access to the interior of the cabinet. If this is the case, it’s important to turn off the furnace and call a professional to remove the dead animal and clean the furnace.

The odor can also come from elsewhere in the HVAC system, like the insulation or ductwork. Services like professional duct cleaning may be necessary if this kind of smell is rooted deep in the ventilation.

5. Furnace Smells Like Smoke

If your furnace smells like smoke, it may be caused by dirty air filters or other components that have accumulated lots of dirt. In this case, it’s recommended to turn off the furnace and replace the air filters. You can shop online for scented air filters to help combat this problem, and tell your friends or family to smoke outside of the house. 

6. Furnace Smells Like Exhaust

It’s possible that the furnace’s air intake is drawing in contaminated air from the outside. This can happen if the air intake is located near a source of car exhaust, such as a garage or a busy street. The odor can also be caused by a malfunctioning furnace that is not properly venting the exhaust gases from the flue pipe.

In this case, it’s recommended to turn off the furnace and call a professional to inspect the furnace and its ventilation system. A professional can determine the source of the problem and recommend a course of action to correct it and eliminate the odor.

Avoid a Smelly Furnace with Help from Simons

Whenever you notice something unusual about your heating, from foul odors to loud noises, contact Simons Heating & Cooling. We’ll get to the bottom of it and keep your furnace running (and smelling) great! Give us a call today at 518-535-1870 to get started.

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