bad smell coming from ac

When an air conditioner produces an odor along with cool air, your home will no longer be a comfortable place to rest and relax. AC smells can be caused by a variety of factors, including dirt, mold, mechanical malfunctions, moisture, pests, and more. If your air conditioner smells bad when turned on, it’s important to take action right away. Poston Brothers Heating and Cooling can find the source of a smelly air conditioner and fix the underlying cause quickly. Learn the reasons behind common ac smells and what to do when you notice them.

Why Your Air Conditioner Smells Bad When Turned On

If your air conditioner smells bad when turned on, there could be something in the system that shouldn’t be there, or a normal part of the system may not be working correctly. Some air conditioner smells can be resolved quickly on your own, while others will require the help of a trained HVAC technician to conquer.

Here are some of the most common odors reported when your central air conditioner smells bad when turned on, and their causes.

Lingering Household Odors

Cigarette smoke, pet hair, cooking aromas, cleaners, and more – these things can all stay behind in your home, hiding in your air conditioning equipment instead of being expelled outdoors as exhaust. These particles become trapped in the system and produce an unpleasant odor whenever the cooling system runs.

These particles commonly become trapped in a dirty air filter or on a filthy evaporator coil. Regular maintenance and air filter replacements can help prevent this reason why your air conditioner smells bad when turned on. Whenever you notice these smells, perform some cleaning to your ac unit right away to eliminate them. The air filter should be replaced as needed, which can be every 1 to 12 months depending on the model and your home. The evaporator coil should be cleaned every 6 to 12 months.

Moldy, Stinky Feet Smells

If your ac smells musty, it’s likely that mold or mildew is growing somewhere in the system. Mold commonly grows within the ducts or on the evaporator coil of the indoor unit.

If your home air conditioner smells like stinky feet when turned on, this could also indicate mold or mildew growth too. This usually means that there is water trapped in the system somewhere, which can lead to the growth of mold and mildew. The drain pan may be full of stagnant water and the condensate drain system clogged.

  • Use a wet/dry vacuum to remove standing water from the drip pan. Clean the drip pan with bleach or vinegar to prevent further mold growth.
  • Remove materials clogging drain lines using a garden hose, long wire, cleaning brush, or another household tool. If you are unable to clear the line, call a heating and cooling company to make the repair.

A Foul, Rotten Smell

Homeowners often complain that the air conditioner smells bad when turned on before discovering a pest or vermin infestation in their home. Insects and small critters can access your home from outside and chew through materials to infiltrate the ducts. Rodent and bug droppings, a dead animals, and other pest matter cause odors. Commonly the area where they nested is typically the source of the odor that makes a strong air conditioner smell.

Have a pest control provider inspect the system and treat any active infestations. In addition to addressing any pests, it’s also important to have your ducts cleaned and check your air conditioning unit for signs the pests accessed these areas. Make repairs to vent covers and other exterior barriers to prevent access into your HVAC system.

Burning or Electrical Odors

One of the most common reasons an air conditioner smells bad when turned on is because of overheating components. Electrical odors can be caused by several different components, including circuit boards, fans, blower motors, compressors, and more. An air conditioner burning smell or an electrical odor can go hand in hand with damage and the need for replacement. If you’re noticing a burning smell, call an HVAC technician to make the necessary repairs right away to prevent as much damage as possible to your air conditioner unit and the impacted parts. 

Chemical Smells

When noticing an air conditioner smell that is sweet, chemical-like odors are commonly caused by a refrigerant leak. If you’re experiencing a sweet chemical odor similar to chloroform or ether, it’s likely due to coolant escaping the system. The best way to get rid of this smell is to ventilate the home. This will help to prevent exposure and toxicity. Call your heating and cooling company, as an HVAC technician must find the refrigerant leak, make repairs, and refill the system with the proper volume of refrigerant.

AC Repairs in Burlington, KY

If your air conditioner smells bad when turned on, the cooling system may need repairs. Call the Poston Brothers Heating & Cooling team to make an appointment for air conditioning system repair today.