Why Does My Air Conditioner Smell?

A woman sitting in a kitchen and holding her nose because of a smelly air conditioner.

If bad smells are wafting from your AC unit, it’s completely understandable if you’re concerned. The HVAC systems in our homes have many moving parts — and if one of these components gets damaged, worn, or broken, you could be facing more than just a smelly inconvenience.

Why does your air conditioner smell? This question isn’t always straightforward to answer because it depends on the circumstances. The unfortunate truth is that air conditioners can produce a wide range of odors — some even more unpleasant than the next. The good news, though, is that these various smells make it easier to identify the root of the problem.

Below, we’ll go over some of air conditioning systems’ most common odors. Once you understand what you’re dealing with, you can put a plan in motion to fix it once and for all. There’s absolutely no reason why you should have to live with a smelly AC forever.

Something Musty

When you hear the word “musty,” you probably immediately think of mold. Since mold grows in excessively damp places, a buildup of condensation may be what causes your air conditioner to smell. Of course, any kind of mold growth can be a major issue, as it can affect your indoor air quality and comfort.

What causes this excessive moisture to collect inside your AC unit? The two most common culprits are a clogged drain line and a dirty evaporator coil. Your air conditioner produces condensation as part of the cooling process, and your drain line will usually remove this moisture quickly. However, if the drain line is clogged, the condensation won’t have anywhere to go — which means it will sit inside your AC and create a musty smell. The smell might also be similar to dirty socks in some instances.

Dirty evaporator coils can also produce this smell since they can become frozen over time. When this happens, the coils will harbor condensation that could contribute to that stinky-sock smell. You’ll also want to check that your HVAC unit’s air filter is clean; a clogged or dirty filter can also create bad odors.

Something Burning

Why does your air conditioner smell like gunpowder or burning plastic? These odors usually have to do with a component malfunction or electrical issue. Burning circuit boards and broken fan motors are some of the most common culprits.

However, you should also take into account how long it’s been since you last used your AC system. If the weather has recently warmed up and you’ve just turned your air conditioner on for the first time this season, burning smells can be normal.

If the smell has been around for a while, though, you’ll want to contact a professional HVAC technician as soon as possible. When it comes to burning odors, it’s not always easy to know what causes your air conditioner to smell. Fortunately, a trained technician will be able to get to the bottom of the problem once and for all.

Exhaust Fumes

Your air conditioner shouldn’t create a smell, so every odor is cause for concern. However, finding the scent of exhaust fumes in your home can be doubly horrifying. So, why does your air conditioner smell like a car’s exhaust?

It’s possible that you have a refrigerant leak on your hands. Your air conditioning system heavily relies on refrigerant, a working fluid, during the cooling process. Unfortunately, as our cooling systems age, they can experience significant wear and tear. One potential outcome of this damage is a refrigerant leak.

If you have a refrigerant leak, it’s best to quickly contact an HVAC technician. While an HVAC repair in Cumming, GA, can sometimes fix the problem, you might want to consider a full replacement if the unit is getting old and you’re constantly scheduling repairs.

Rotten Eggs

What causes your air conditioner to smell like rotten eggs or sulfur? If these odors are in your home, you should know that the problem probably doesn’t have to do with your air conditioning unit. Instead, there could be a dead animal in your ducts or a natural gas leak.

If you’re dealing with a dead animal, you should contact pest control to remove it. It’s always a good idea to have a professional handle this job since it is the safest option. If you suspect you have a gas leak, you also shouldn’t hesitate to call a professional. Gas leaks can be dangerous, so evacuate your home as soon as you can.

Schedule an Air Conditioner Service With the Pros

Why does your air conditioner smell? As you can see, this question can have many different answers. There are many AC smells you can encounter, and all of them should be handled with extreme care.
Whether you’re dealing with a burning smell or exhaust-like odor, Gagne Heating & Air Conditioning is here to help. Our technicians have been assisting residents of the Greater Metro Atlanta with their heating and cooling needs for decades. We can help determine what causes your air conditioner to smell and will ensure that everything is working correctly. Contact our HVAC contractors in Atlanta, GA, to learn more about our residential and commercial services!