Skip to Content Top

When Your AC Smells – Reasons & Solutions

when your AC smells

If your Air Conditioner smells funky, or something other than cold, clean air, that is a sign something could be seriously wrong with your AC. In this post, we’ll cover the most common types of smells, some of the reasons for them, what you can do to get rid of them and recommendations for when to call for AC repair.


If your AC smells like stinky feet or a locker room, chances are you have a soiled evaporator coil, the result of bacteria, fungus, mildew, and mold growth. If your AC still has some life left in it, an inspection, tune-up, and full system cleaning should typically solve the problem. However, if you want to eliminate the smell for good, schedule a routine service to ensure the evaporator coil is clean and the drain system is unclogged as well.

Car Exhaust

There’s no reason your AC should ever smell like exhaust from a running car and if it does, means you likely have a leak in your refrigerant line which in turn, can impact your AC’s performance. It also releases chemicals into the air and can be hazardous for the environment. Freon, a commonly used refrigerant in air conditioners, absorbs heat from the indoor air and releases it outside This kind of leak smells like sweet chloroform or your car’s coolant but with a sweetish odor. Even though it’s an almost odorless gas, you can still detect the smell. Freon doesn’t linger around in the air for long and drops down to floor level quickly. If your AC is emitting a chemical-like smell, get it checked promptly by a certified HVAC specialist who can repair it in no time. In the meantime, crack open your windows and make sure your home is ventilated to reduce the smell and prevent any hazardous effects.

Rotten Eggs/Sulphur

If your AC smells like rotten eggs when you turn on it could be a potential gas leak that’s gotten into your ductwork. If this is the case, open your windows, leave your house immediately and call your gas company, and don’t use any electronics or open flames near the area where you smelled the natural gas as natural gas is a hazardous substance and doing so could lead to an explosion or fire.


A foul or rotten smell usually indicates a bird, lizard, or other critter has gotten into your ductwork and is stuck or started to decompose inside your equipment. The faster you can identify it, the better. You will need to remove it yourself or contact your AC professional to help locate it. Turn off your AC if you can and open some windows. You’ll have to locate the exact duct where the stench is coming from and use a screwdriver to remove the cover. Carefully remove the carcass, which can be tricky, and if you don’t see it right away, you might need a flashlight to locate it. Once you find and remove it, clean, and dry the area and have your ductwork checked and cleaned by your AC professional to ensure nothing is damaged and to seal any entry points.

A bad-smelling air conditioner can be just as aggravating as an underperforming one since neither provides you with the comfort you desire.

Don’t wait for a bad smell to happen, prevent them from happening by checking and changing your air filters, and keeping up with your regularly scheduled AC maintenance program. Call Anthony’s at (941) 347-0779 to take care of all your AC needs…we care about your Home and Family’s Comfort and Safety.