Funny or unpleasant smells emanating from your air conditioner can negate the comfort you normally experience when you enter your home on a hot day. Odors can also be a sign of a more serious problem.
There are several potential causes of odors from your air conditioner. The type of smell is a clue to its origin. Learn more about what different smells mean.
Dirty socks or feet = mold, mildew, fungus
This is a common occurrence with air conditioners and is most likely the result of water accumulating in the drain pan, drip lines or ducts. The standing water can cause fungus, mold or mildew to grow. Dirty air filters can also create the smell as they accumulate moisture. Contact a professional to thoroughly clean the lines and ducts, and repair the source of the leak to prevent further problems.
Exhaust fumes = fluid leaks
If your air conditioner smells like your car’s exhaust it could mean a fluid leak. Some of the fluids in your AC, when heated, can give off that smell. Most likely it is a leak in the refrigerant line, which can impact the performance of your unit and cause hazardous environmental exposure.
Rotten eggs = gas leak
This smell is highly concerning. Gas distributors add that sulphuric/rotten eggs odor to otherwise odorless gas to alert homeowners to a gas leak. It may also smell like skunk spray. Immediately turn off the gas supply, contact your utility company or the fire department from a safe location outside your home.
Trash smell = dead animal
A foul or rotten smell could be dead rodents. Other critters, such as birds and insects, can nest in the system and become trapped in the equipment. Over time they emit these unpleasant odors. Pest-proof your equipment to avoid this scenario.
Cigarettes = odor from smoke accumulating in the filter and evaporator coil
If you or someone else smokes in your home, your AC can absorb the odors from embedded tobacco particles in the filter and evaporator coil. When the system turns on, the particles are knocked loose and travel back into your home. Change the filter often and restrict smoking to outdoors.
Burning = overheating motor, wiring or mechanical problem
The smell of burning gunpowder or plastic could mean that one or more electrical components are burning or there is a short. These could be circuit boards, power wires, fans and compressors, or others. Alternatively, the smell could be the result of dust on a system that hasn’t been used in a long time. If the smell doesn’t go away on its own once the system has been running for a while, or if it gets stronger, turn off the unit and call for service right away.