Why Does My Air Conditioner Smell Strange?

Firing up your air conditioner to stay cool is a pretty standard and expected part of summer, but foul odors coming from your cooling system certainly aren’t. A strange smell coming from your air conditioner can be a source of serious concern, so it is important to identify what might be causing it so you can figure out whether you might have a serious issue to fix. However, air conditioners are complex, so identifying what might be causing a smell is a trickier challenge than you might think.

Here are a few of the strange smells you might encounter with your air conditioner and what each of them could indicate about your system as a whole.

Burning Plastic/Rubber Smell

A burning plastic or rubber smell could be exactly what you think it is: burning rubber or plastic. Typically, this happens when too much current flows through an electrical wire, causing the wire itself to get extremely hot and the shielding around the outside to begin to melt or burn. This is usually a sign that either some critical component of your air conditioner’s electrical system has failed, or something is allowing your air conditioner to receive far more electrical current than it should. In either case, this is a serious problem that could have disastrous consequences and should be taken seriously. Shut down your air conditioner at your circuit breaker panel and call a professional to have the problem diagnosed and repaired as soon as possible.

Mildew/Mold Smell

A mold or mildew smell is typically a symptom of excessive moisture in your air conditioner, notably when that moisture contributes to mold or mildew growth. Mold growth is fueled by three ingredients: protection from sunlight, a carbon-based food supply, and a steady supply of moisture. All of these ingredients can be found in an air conditioning system, particularly if water extracted from the air in your home can’t drain out of your drain pan.

If your air conditioner drain line is clogged, blocked, or otherwise not running properly, the buildup of water could contribute to mold growth which can then reach the inside of your air ducts. Removing mold from air ducts is a tricky and labor-intensive job, so we recommend having it done professionally if you start to smell this distinct, musty odor in your home.

Sweat/Stinky Sock Smell

This is an issue similar to mold or mildew smells, although you might only smell it coming from your air conditioner’s condenser coil and indoor unit as a whole rather than throughout your entire home. When standing water mixes with bacteria, it can create colonies that produce foul-smelling odors that resemble a gym bag after a sweaty workout or stinky socks that have been on your feet all day. While the good news is that this smell doesn’t usually travel through your home, the bad news is it can be rather difficult to get rid of without an extensive and labor-intensive cleaning process (after the clog in your drain line is cleared away properly).

Skunk-Like Smell

Anybody who has been anywhere around a skunk that has recently sprayed will likely never forget the odor anytime soon. The foul stench they produce is as terrible as it is unique, and it’s easily identifiable to anyone who is familiar. A skunk-like smell in your air conditioner probably doesn’t mean a skunk has gotten stuck in your system, but rather that your air conditioner is leaking gas. Specifically, methyl mercaptan—a common ingredient in many synthetic refrigerants—smells an awful lot like a skunk spray.

Methyl mercaptan is a toxic gas and the fumes could put you and your loved ones at risk. If you ever smell this nasty odor coming from your air conditioner, shut it off immediately, evacuate your home, and call a cooling professional to schedule a repair service as soon as possible. We do not recommend turning it on again until you are certain the issue has been properly fixed.

Sulfur/Rotten Eggs Smell

Finally, the sulfur smell of rotting eggs is another distinct odor that is hard to forget. Likewise, it’s an odor that shouldn’t be anywhere near your air conditioner. This distinct smell is typically one associated with death and decay and could be an indication that an animal has died in your air ducts. Animals getting into air ducts isn’t anything new or unheard of—in fact, it’s quite common for birds and small rodents to make their home in ducts thanks to the large amount of space and shelter from the elements. During winter months, in particular, it isn’t uncommon for animals to seek shelter in air ducts where warmth is plentiful. However, sometimes animals get in and then can’t get out, and they eventually die in the ductwork. Removing the odor is possible with a professional duct cleaning service.

If your air conditioner is emitting a strange smell or odd sound, call the team at Roby Services at (704) 753-7754 today!