HVAC Odors: How to Identify & Get Rid of HVAC Odors

How to Get Rid of HVAC Odors

Causes and solutions to various HVAC odors
Read Time: 4 minutes
Jul 1, 2020
Inspecting a Home Air Vent for Maintenance

You rely on your HVAC system to make your home a comfortable haven. If your conditioned air suddenly has an odd or unpleasant smell, your comfort can quickly decline. Locating the source and eliminating odors that originate in the HVAC system can restore your comfort, and it can protect everyone in the household from potential health and safety hazards too.


Your HVAC air output can carry a bad smell for a variety of reasons, but before you can get rid of the odor, you’ll need to pinpoint the source. Keep in mind that not all unpleasant odors are caused by malfunctions within the HVAC itself. Scents can be picked up by your unit and distributed throughout the house, causing the illusion that the HVAC is to blame for the scent.

Here are some common kinds of HVAC odors and their likely origins, and some advice on how to get them resolved:

Chemical Scents

If your conditioned air has a distinct chemical smell, it likely contains a buildup of off-gassed VOCs from everyday household products and materials. To get rid of the odor and improve your air quality, ask your HVAC professional about installing a ventilation system or adding an air-cleaning unit to your HVAC system.

Acrid Burnt Odors

This kind of metallic scent is usually an indicator that electrical components in your HVAC system are overheating, like a capacitor, circuit board or motor. To prevent a fire, shut down the system until your HVAC technician can investigate what’s wrong and fix the problem.

Lingering Scents

Chocolate lab sitting against white wall

If your home has taken on a wet dog smell or picked up a permeating cigarette scent, there isn’t necessarily a need to be alarmed. Your HVAC will pick up on strong scents and hold onto them in the filter. To rid your home of these non-threatening, unwanted smells simply change out your air filter. In more intense cases this may also require professional cleaning to completely rid your home of the scent.

Moldy and Musty

This isn’t a sign of danger, but it is a sign of poor air quality. Mold could be growing out of sight. In order to fix this problem issue a maintenance program with the help of a professional. UV light installation will also help to cut back on mold growth and with the musty smell in your home.

Acetone Fumes

If you get a nail polish remover-like odor from your HVAC vents, the most likely cause is a refrigerant leak. This is another odd smell that needs prompt professional attention because a leak can end up ruining a costly component like the compressor if enough refrigerant is lost.

Dirty-sock Syndrome

The foul smells caused by the growth of mold, mildew, bacteria, and algae in an HVAC system are a common occurrence. They’re fairly easy to eliminate, but you may need expert help to isolate and thoroughly clean the source. Frequent culprits are a clogged cooling coil or air filter, moisture and debris in the ductwork, or blockages in the condensate drain.

Rotten Egg Smell

Not only is this smell unpleasant, it’s also an indicator of potential danger. If your HVAC begins to smell like rotten eggs take action immediately. This is likely a sign of a natural gas leak. Turn off your AC and get out of the house immediately. Your gas company will be able to help you with next steps.

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Dried P-traps will result in a sewage smell as sewer gases back up into your home. To prevent this from happening simply run water in your sinks each month, especially the ones you don’t regularly use.



If not properly maintained, parts within your HVAC system are more susceptible to producing unpleasant odors. Keep a close eye on these areas of your HVAC system to prevent bad odors before they start:

Air Ducts

Tears in air ducts can allow outside odor to creep in, eventually being filtered into the interior of your home. Alternately, if water damages the air ducts mold can grow, causing a musty smell.


Regularly changing your air filter can cut back on bad odors being spread around your house by your HVAC. You should change your air filter every 90 days.

If you have pets this drops to every 60 days and if you use your space as a vacation home it jumps up to every six months.

In cases where inhabitants have allergies or multiple pets, it’s wise to change the filter every 45 days.

When to Change Your Air Filter

Vacation Homes Every 180 Days
Average House Every 90 Days
Homes with Pets Every 60 Days
Multiple Pets or Allergies Every 45 Days
Full Set ~26 months


Some odors are out of your control. Others, however, have everything to do with your own bad habits. By changing your HVAC-related habits you can improve your air quality and cut down on strange scents taking over your house.

  • Regularly change your air filter
  • Turn on exhaust fans when showering or cooking
  • Use HVAC odor blockers to eliminate bad scents
  • Clean your home often to remove strange smells


As a homeowner, you have to learn the line between a problem you can fix and when you need to call in the pros for assistance. If you notice an alarming scent like the rotten egg smell discussed above then immediately contact your HVAC professional.

Some scents come with easy solutions. But if any odors persist despite your efforts to resolve the issue this is another sign that the solution may be outside your scope of abilities. Make sure that whoever is hired to fix your problem is certified and holds the required permits.

Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems). For expert help, eliminating odors in your Orlando home’s HVAC systems, contact us by filling out the form below.

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