Where Does the Stench from My AC Come From?

Posted: 2021-06-24

Even when it gets really hot outside, you can still enjoy this summer while staying at home — thanks to your air conditioner. Running your AC is necessary not only for your comfort, but also to clean your indoor air and keep you from the effects of extreme heat.

But there are times when you notice awful smells coming from your cooling system, and you probably want to find out where it originates. Before we give you any information about the causes, let us remind you that foul odors should not be taken lightly, so read on to know what you can do.

Four Seasons Air Specialists is your trusted HVAC company in Shoreview MN. We are experts at AC diagnosis — we can help get rid of foul odors from any air conditioner.

Here are some of the most common AC smells and what they mean.

Cigarette Smoke Smell

If you have smokers at home, chances are, the AC will eventually end up smelling like tobacco smoke. The AC’s evaporator coil and filter absorb the odor from cigarette smoke, then the indoor unit sends it back into your home through the vents. Not only is this smell unpleasant, but it also can cause headaches and allergic reactions.

Changing your filters or keeping them clean can help eliminate the cigarette smell from your AC. Also, it’s best if you can smoke outdoors to prevent the air conditioner from sucking the smoke.

Rotten Egg Smell

No one wants the stench of a rotten egg, but your AC can produce this odor and it shouldn’t be ignored. This problem can be caused by several things, including a decomposing animal within the ductwork. Rodents and birds have their ways of getting into your home, and if they die and decompose, they will release a dreadful smell. When you turn the AC unit on, it will circulate that smell throughout your home. 

You have to detect and eliminate the dead animal as soon as possible to expel the putrid odor. If you’re uncomfortable taking this task, call your preferred HVAC company.

 If it isn’t an animal causing this kind of stench, there may be a natural gas leak in your home. If you smell rotten eggs coming from your AC, be sure to open all the windows immediately and get out of the house. Call your gas company to deal with the leak and contact a qualified HVAC professional to inspect your cooling system.

Car Exhaust Smell

Unlike your furnace, your air conditioner does not run on an internal combustion engine. Therefore, if your AC releases a smell that’s similar to a running car’s exhaust, it tells you there’s a problem. This kind of smell can come from a leak in your refrigerant line, which can greatly diminish your AC’s performance. It can also release chemicals that are dangerous to the environment.

This smell should not be passed over. When your AC emits chemicals and produces exhaust smells, call a qualified technician right away. Try not to DIY this issue, especially if you do not have the training. What you can do is air out your home by opening the windows to release the smell.

Moldy Smell

HVAC systems may release a smell like mildew or mold because of the condensation that takes place as the unit is running. When the moisture doesn’t drain properly, it can get into the ducts, causing the formation of mold.  In the summer, turning your AC off while keeping the house closed will cause higher humidity levels. Therefore, it’s best to just keep the air conditioner running to allow the unit to control your home’s humidity and avoid mold development.

The easiest way to get rid of this smell is to locate the mold buildup and clean it thoroughly. This will require some skill and experience as well as the right tools. If you find this a little too challenging, your preferred HVAC contractor can do it for you.

Get Rid of Foul AC Smells. Call the Experts

If you are dealing with any of these four issues, or any other irksome smell from your AC, call Four Seasons Air Specialists, your trusty Circle Pines AC repair company. We have teams of HVAC experts who can detect the problem’s cause and apply appropriate solutions.