Nine Suspicious AC Smells and What They Mean

Air conditioning is an essential part of modern living, particularly during the hot summer months. When you use your air conditioner, you expect nice, cool, refreshing air to fill your home. But once in a while, AC units produce unusual 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 suggest a severe problem that requires immediate attention. When you have a question, turn off the unit and contact an HVAC technician to look a little more closely. Meantime, learn about nine weird AC smells and what they might mean. 

1. Rotten Eggs 

A rotten egg smell could point to 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 reason for this smell. If you detect a rotten egg smell originating from the vents, turn off your air conditioner ASAP, open the windows for ventilation and evacuate the house. Following that, call an HVAC contractor promptly to inspect for a gas leak and complete the necessary repairs. 

2. Musty Odors 

A musty smell normally denotes mold or mildew developing inside the AC unit or ductwork. These microorganisms flourish in damp, dark environments, making the evaporator coil and air filter likely places for mold to develop. To remove the musty smell and deter further mold growth, hire a professional to clean your air conditioner, replace the filter and find any other sources of moisture. 

3. Tobacco Smoke 

If someone in your home smokes, odds 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 on a regular basis and plan routine maintenance to help prevent this AC odor. Also, it would be wise to not smoke inside the house. 

4. Sewage 

If you detect a sewage smell from your HVAC system, your plumbing or sewer system may actually be the issue. The smell may be brought about by methane gas emitting from a busted or clogged 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 filthy air conditioner with a buildup of bacteria and fungi can emit a smell reminiscent of dirty socks. This odor may be notably strong when you turn 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 dead animal or animal poop inside the ductwork. It’s possible a sick or injured bird, rodent or other pest climbed inside an air duct during the winter, where it died and began rotting. This is a health hazard, so reach out to an HVAC technician to tackle the problem. 

7. Electrical Burning or Gun Powder 

If your AC releases a burning smell, it’s possibly due to an electrical issue, such as a damaged motor, circuit board, compressor or wiring. If any of these parts overheat, they may give off a burnt, gun powder-like smell. To reduce the risk of irreversible damage, turn off the AC immediately and get in touch with an HVAC technician to diagnose and correct 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 major health and environmental hazard, so shut down your air conditioning 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 located in the garage, even a car’s idling exhaust could mingle with the indoor air. These are serious concerns that could call for sealing the ductwork or even redesigning your HVAC system. 

Schedule Air Conditioning Repair 

If you’re concerned about a weird smell coming from your air conditioner, consider Service Experts Heating, Air Conditioning & Plumbing for the repair you need. We use advanced diagnostic equipment to promptly and accurately determine the problem. Then, we’ll summarize the most cost-effective repair methods and present recommendations to prevent a recurrence. We believe in our quality work so much that we insure every repair with a one-year 100% satisfaction guarantee! Phone a Service Experts office near you for additional details or to request air conditioning repair in the U.S.. 

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