What Could Be Causing Odd Air Conditioning Odors?

Unless there is a candle lit or cookies in the oven, most homeowners will agree that the best thing to smell in the home is nothing at all. Unfortunately, things happen and sometimes you’re met with an odd smell that you can’t quite put your finger on. In terms of odd air conditioning odors, there are a few common scents worth familiarizing yourself with.


Due to an inability to drain moisture properly, mold or mildew can begin to grow inside of your air conditioner. Mildew is the most common odor that an air conditioner emits and is an easy fix.

Smelly Feet

If your home begins to smell like feet, it is likely because of stagnant water in your A/C unit. Having your unit cleaned and repaired so that it can effectively drain water should get rid of the smell.


While unpleasant, the smell of rotten garbage is rarely caused by a big issue and is usually the smell of a dead animal. There is no need to call animal control; an HVAC technician can be notified and he or she will have the animal removed.


First and foremost, turn your A/C unit off and call an HVAC technician as quickly as possible. A burning smell can be the result of a mechanical problem and is not something to take lightly. In the case of a burning smell, you are always better safe than sorry.


While both have smoke-like scents, the smell of old cigarettes is wildly easier to fix than a burning smell. If you are a smoker or live with smokers, the cigarette’s fumes can take up residence within your A/C unit’s evaporator coil. The smell is caused by those fumes being blasted out of your A/C vent every time you turn on your air conditioner.

Rotten Eggs or Sewage

These are two smells that no one wants to fill their home. In regards to the former, it is imperative that you leave your home at once. A rotten egg smell is usually caused by a gas leak and your gas company should be notified immediately. The latter odor, sewage, could be caused by a backed up or ruptured sewer line. Aside from an HVAC tech, your local plumber should be notified at once.

Odd smells happen, but you don’t have to live with them. Contact ServiceFirst Heating and Cooling at 360-591-7274 to speak to a certified HVAC contractor about your concerns and to schedule an appointment to remedy them.