We're Hiring! Looking For Technicians! Read More

Skip navigation

37 Years In Business

24/7 24/7 Emergency Service Available:



Collier's Heating & Air Conditioning Blog

“Dirty Sock” Syndrome and Your Air Conditioning


The name “dirty sock syndrome” will give you a heads-up about why this isn’t something you want happening your home. If you instantly wrinkled your nose and imagined a damp, musty, moldy, thoroughly unpleasant odor—well, you’re right. When you’ve got dirty sock syndrome happening in your house, you can expect this unwelcoming smell to permeate throughout the rooms connected to the ventilation system.

What’s causing this?

No, it’s probably not a dead animal in the ductwork. (That can sometimes happen, but the smell isn’t like unwashed socks. It’s actually worse, if you can—or want to—imagine it.) The source of dirty sock syndrome is with your air conditioner. Specifically, mold and mildew and your air conditioner.

First things first, dirty sock syndrome is rarely dangerous. When people hear the word mold in connection to their house, they often get a bit panicky about harm to the air quality. Thankfully, most of the time dirty sock syndrome has more to do with mildew than mold, and only a small number of molds release spores that are harmful to humans. The situation is worse if there are asthma and allergy sufferers in your home, in which case the dirty sock syndrome ought to be taken care of ASAP. But you’ll want to get rid of it no matter what since it’s just not a great odor to have around your home, and it isn’t good for the air conditioner.

Why Is There Mildew and Mold on the AC?

Mildew and mold can grow any place where there’s sufficient moisture. High humidity in summer offers many opportunities for both to develop in a home. But the concern is higher with an air conditioner because of the moisture the AC draws out of the air as it operates. This moisture gathers across the indoor evaporator coil of the air conditioner. Most of the water drips off the coil and into a condensate pan, where it’s pumped away. But residue can allow mold and mildew to grow along the coil.

Because the blower fan sends air around the evaporator coil, the smell of mold and mildew ends up moving around the house—and, presto: you have dirty sock syndrome. Aside from the sweaty gymnasium smell, dirty sock syndrome is bad news for the AC. The layer of growth on the evaporator coil forces the air conditioner to work harder to do its job, raising bills and lessening system life.

What Can I Do about Dirty Sock Syndrome?

First, always take good care of the AC and see that it has routine maintenance in spring to make it harder for moisture to build up. If dirty dock syndrome still becomes a problem, we recommend the installation of a UV air purifier. This purifier directs ultraviolet light at the evaporator coil, which kills off mold and mildew and prevents them from growing again.

You can trust us for any AC services, such as air conditioning maintenance and air conditioning repair in Warsaw, IN. We also install UV air purifiers and other indoor air quality measures.

For over thirty years, a company you’ve grown to trust: Collier’s Heating & Air Conditioning.

Comments are closed.

Mail icon Join Our Mailing List: