AC Smells Guide

Air conditioning is an important part of modern indoor comfort, even more so during humid summer months. When you run the air conditioner, you want pleasant, cool, refreshing air to enter your home. But from time to time, AC units give off unusual or concerning odors that make you worry if something’s wrong.

A strange smell emitting from your air conditioner or ductwork might be no big thing — or it could signal a severe problem necessitating immediate attention. When in doubt, power down the unit and contact an HVAC technician to check it out. Right now, find out about nine weird AC smells and what they might mean.

1. Rotten Eggs

A rotten egg smell could indicate a gas leak in your HVAC system. Air conditioners don’t run on natural gas, but they use the same blower and ductwork as your furnace, which could be the real cause for this smell. If you become aware of a rotten egg smell coming from the vents, turn off your air conditioner immediately, open the windows for ventilation and exit the house. Following that, call an HVAC contractor at once to check for a gas leak and perform the necessary repairs.

2. Musty Odors

A musty smell usually suggests mold or mildew growth inside the AC unit or ductwork. These microorganisms flourish in damp, dark spaces, making the evaporator coil and air filter common places for mold to take hold. To deal with the musty smell and prevent further mold growth, hire a specialist to clean your air conditioner, replace the filter and find any other sources of moisture.

3. Cigarette Smoke

If someone in your home smokes, chances are the AC will start smelling like stale cigarettes eventually. The buildup of nicotine and other chemicals inside the unit, air filter and ductwork enters into your home every time the air conditioner operates. Change the filter schedule routine maintenance to help minimize this AC odor. Also, it would be wise to not smoke inside the house.

4. Sewage

If you perceive a sewage smell from your air conditioner, your plumbing or sewer system is likely to be the problem. The smell may be brought about by methane gas emitting from a broken or blocked sewer pipe or a dry drain trap, which has managed its way into the ductwork. Methane is dangerous, so if you smell a sewage-like AC odor, contact a plumber without delay.

5. Stinky Feet

A filthy air conditioner with a buildup of bacteria and fungi can emit a smell that reminds you of sweaty socks. This odor may be particularly strong when you turn on the AC for the first time in the spring. Regular cleaning and maintenance assists you to prevent this odor from developing.

6. Skunk Smell

If you smell a skunk-like odor coming from your AC unit, there may be a decayed animal or animal waste inside the ductwork. It's possible a sick or injured bird, rodent or other pest climbed inside an air duct at some stage in the winter, where it died and began rotting. This is a health hazard, so contact an HVAC technician to address the problem.

7. Electrical Burning or Gunpowder

If your AC releases a burning smell, it’s probably due to an electrical issue, such as a compromised motor, circuit board, compressor or wiring. If any of these components overheat, they may emit a burnt, gunpowder-like smell. To reduce the risk of permanent damage, turn off the AC immediately and contact an HVAC technician to diagnose and remedy the issue.

8. Car Exhaust

A smell comparable to car exhaust could indicate a refrigerant leak. Refrigerant is the chemical your air conditioner uses to pull heat from the indoor air and exhaust it outside. A leak can be a serious health and environmental hazard, so power down your air conditioner and call for help.

9. Chemical Fumes

A chemical-like smell originating from your air vents could be sourced to close by vehicles, cleaning products, paints, adhesives or other toxins. If your AC blower fan motor is situated in the garage, even your car or truck's idling exhaust could mingle with the indoor air. These are grave concerns that could call for sealing the ductwork or even redesigning your HVAC system.

Schedule Air Conditioning Repair

If you’re thinking about a weird smell coming from your air conditioner, consider Service Experts for the repair you need. We use superior diagnostic equipment to quickly and accurately determine the problem. Then, we’ll share the most cost-effective repair methods and provide recommendations to prevent a recurrence. We believe in our exceptional work so much that we insure every repair with a Service Experts Guarantee! Speak to a Service Experts office near you for additional details or to request air conditioning repair in the U.S.