Nine Strange AC Odors and What They Mean

Air conditioning is a necessary part of modern living, particularly during humid summer months. When you turn on your air conditioner, you anticipate wonderful, cool, refreshing air to flow into your home. But once in a while, AC units release odd or concerning odors that make you curious if something’s wrong. 

A strange smell generating from your AC unit or ductwork might be no big thing — or it could indicate a serious problem requiring urgent attention. When you have a question, switch off the unit and connect with an HVAC technician to check it out. Right now, read about nine weird AC smells and what they might mean. 

1. Rotten Eggs 

A rotten egg smell could suggest a gas leak in your HVAC system. Air conditioners don’t function on natural gas, but they share a blower and ductwork with gas-fired furnaces, which could be the actual root cause for this smell. If you become aware of a rotten egg smell originating from the vents, turn off your air conditioner immediately, open the windows for fresh air and exit the house. Then, call an HVAC contractor right away to inspect for a gas leak and perform the necessary repairs. 

2. Musty Odors 

A musty smell typically denotes mold or mildew developing inside the AC unit or ductwork. These microorganisms flourish in damp, dark conditions, making the evaporator coil and air filter well-known places for mold to take hold. To get rid of the musty smell and prevent further mold growth, hire an expert 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 start smelling like stale cigarettes in the near future. The buildup of nicotine and other chemicals inside the unit, air filter and ductwork circulates into your home every time the air conditioner turns on. Change the filter monthly (if necessary) and arrange for routine maintenance to help counter this AC odor. Also, it would be sensible to not smoke inside the house. 

4. Sewage 

If you perceive a sewage smell from your HVAC system, your plumbing or sewer system could have a problem. The smell may be created by methane gas emitting from a busted or plugged sewer pipe or a dry drain trap, which has managed its way into the ductwork. Methane is unhealthy, so if you smell a sewage-like AC odor, contact a plumber at once. 

5. Stinky Feet 

A dirty air conditioner with a buildup of bacteria and fungi can emit a smell reminiscent of stinky socks. This odor may be particularly strong when you start up the AC for the first time in several months. Regular cleaning and maintenance helps 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 waste inside the ductwork. It’s possible a sick or injured bird, rodent or other pest climbed inside an air duct over the winter, where it died and began decaying. This is a health hazard, so contact an HVAC technician to deal with the problem. 

7. Electrical Burning or Gun Powder 

If your AC produces a burning smell, it’s likely due to an electrical concern, such as a defective motor, circuit board, compressor or wiring. If any of these parts overheat, they may produce a burnt, gun powder-like smell. To reduce the risk of long-lasting damage, turn off the AC now and call an HVAC technician to diagnose and correct the issue. 

8. Car Exhaust 

A smell identical to car exhaust could imply a refrigerant leak. Refrigerant is the chemical your air conditioner uses to remove heat from the indoor air and exhaust it outside. A leak can be a major health and environmental hazard, so shut down your air conditioner and call for help. 

9. Chemical Fumes 

A chemical-like smell coming 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 located in the garage, even a car’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 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 easily and accurately determine the problem. Then, we’ll explain the most cost-effective repair methods and offer strategies to prevent a recurrence. We believe in our exceptional work so much that we back every repair with a one-year 100% satisfaction guarantee! Phone a Service Experts office near you for more information or to request air conditioning repair in the U.S.. 

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