What Smells Are Normal in Relation to Your HVAC Unit?

March 23, 2021

You expect to feel the heated or cooled air coming from your HVAC system, but you don't expect to smell it. Therefore, any smell coming from your system can be cause for concern. However, some HVAC smells are merely irritating and don't indicate your system is having a serious problem that might require an expensive repair. Let's take a look at some harmless HVAC smells.

Burning Dust

After several months of inactivity, dust will have settled on heating components like the heat exchanger and burners. The dust burns off when the burners ignite. Therefore, it's normal to have a burning-dust smell when you turn on your heating system for the first time. The smell typically dissipates after a few hours. If it persists, you should try replacing your air filter.

Your air conditioner may also emit a burning-dust odor the first few times it kicks on. This is one of those HVAC smells that is usually temporary, so you shouldn't be too concerned. However, if it remains and becomes highly pungent, then call a professional right away.


You're likely to encounter the smell of oil in your home if you use an oil furnace. An oil leak can cause an oily smell. You may need to tighten a fitting, filter, or oil line to remedy the problem. While the issue isn't dangerous, it's best to have it fixed by a qualified technician.

Old Cigarette Smoke

If you or someone else smokes in your house, you may smell cigarette smoke coming from your air conditioner. The cigarette fumes can be drawn into the AC evaporator coil and permeate it. Consequently, the odor will be blasted into your home whenever the air conditioner is running. To fix that, smoke outdoors, change the filter, and schedule a tuneup.

Stinky Feet or Socks

The smell of stinky feet or socks can be caused by:

The solution is a quick repair and cleaning.

Not all HVAC smells are hazardous. However, if you can't tell whether an odor is normal or dangerous, reach out to an HVAC professional. Contact Aggressive Mechanical Contractors to handle all your HVAC repair and maintenance needs in Monmouth and Ocean counties.