Nine Strange AC Odors and What They Mean

Air conditioning is a necessary part of modern living, even more so during the hot summer months. When you use your air conditioner, you anticipate pleasant, cool, refreshing air to enter your home. But occasionally, AC units release unusual or concerning odors that make you wonder if something’s wrong.

A strange smell emitting from your air conditioner or ductwork might be nothing to worry about — or it could indicate a severe problem that requires prompt attention. When you have concerns, switch off the unit and connect with an HVAC technician to look a little more closely. 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 operate on natural gas, but they use the same blower and ductwork as your furnace, which could be the real root cause for this smell. If you become aware of a rotten egg smell emitting from the vents, turn off your air conditioner immediately, open the windows for venting and exit the house. Then, call an HVAC contractor right away to test for a gas leak and complete the necessary repairs.

2. Musty Odors

A musty smell typically indicates mold or mildew developing inside the AC unit or ductwork. These microorganisms multiply in damp, dark environments, making the evaporator coil and air filter likely places for mold to take hold. To get rid of the musty smell and deter further mold growth, hire a specialist to clean your air conditioner, replace the filter and determine any other sources of moisture.

3. Cigarette Smoke

If an individual in your home smokes, most likely the AC will begin smelling like stale cigarettes in the near future. The compounding 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 monthly (if necessary) and {schedule routine maintenance to help minimize this AC odor. Also, it would be sensible to not smoke inside the house.

4. Sewage 

If you perceive a sewage smell from your AC unit, your plumbing or sewer system is likely to be the issue. 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 hazardous, so if you smell a sewage-like AC odor, contact a plumber immediately.

5. Stinky Feet 

A nasty air conditioner with a buildup of bacteria and fungi can emit a smell similar to that of sweaty socks. This odor may be especially strong when you switch on the AC for the first time in the spring. Regular cleaning and maintenance aids to prevent this odor from happening.

6. Skunk Smell

If you smell a skunk-like odor coming from your AC unit, there may be a decayed animal or animal poop inside the ductwork. It’s not uncommon to find that 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 deal with the problem.

7. Electrical Burning or Gun Powder

If your AC releases a burning smell, it’s possibly due to an electrical concern, such as a compromised motor, circuit board, compressor or wiring. If any of these parts overheat, they may produce a burnt, gun powder-like smell. To prevent long-lasting damage, turn off the AC now and get in touch with an HVAC technician to diagnose and fix the issue.

8. Car Exhaust

A smell identical 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 coming from your air vents could be traced to close by vehicles, cleaning products, paints, adhesives or other toxins. If your AC blower fan motor is situated in the garage, even your vehicle’s idling exhaust could seep into the indoor air. These are dangerous concerns that could require sealing the ductwork or even redesigning your HVAC system.

Schedule Air Conditioning Repair

If you’re thinking about a weird smell arising from your air conditioner, rely on Service Experts Heating, Air Conditioning & Plumbing for the repair you need. We use state-of-the-art diagnostic equipment to quickly and accurately identify 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 back every repair with a one-year 100% satisfaction guarantee! Call a Service Experts office near you for additional details or to request air conditioning repair in the U.S..

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