What is Dirty Sock Syndrome?

You turn on the AC, sit back and look forward to some cool, breezy air flow. But you begin to detect an unpleasant odor. Is it mildew? Mold? Does it smell like dirty socks? Why does the house smell like an old gym locker?

The smell has a name, and it’s caused by the buildup of mold and bacteria in your air conditioner. This is a common problem that HVAC professionals have come to refer to as “Dirty Sock Syndrome.” This condition is so named because of the smell’s similarity to dirty sweaty socks that have been lying around for a while. This AC smell can be very pungent and is said to resemble “sweaty feet” or a smell similar to that experienced in a locker room.

The name may sound funny, but “Dirty Sock Syndrome” is a real problem for many homeowners. You’ll typically first encounter this in the spring when beginning to use your air conditioner for the first time in a while. The natural humidity in your home, combined with the buildup of moisture, creates the ideal conditions for this problem to occur.

What causes that dirty sock smell?

“Dirty Sock Syndrome” happens when moisture, dust and dirt on your AC system’s evaporator coil begin to build up over time, inviting mold and bacteria to multiply. Since moisture is trapped in the dust around the coil, it can’t evaporate properly, which can lead to the growth of mildew. When you consider that mildew can feed on the organic matter in the dust, it’s easy to see why “Dirty Sock Syndrome” happens when you have a dirty evaporator coil.

Every time you turn your AC on, this mold and bacteria gets blown into every room of your home, hampering your air conditioner’s performance, efficiency, and introducing mold spores into your indoor breathing air.

Will “Dirty Sock Syndrome” go away on its own?

Arizona homeowners sometimes ask us if “Dirty Sock Syndrome” will go away on its own. Even though you may notice that your air conditioner no longer smells musty as spring turns into summer, that doesn’t mean the problem has gone away. All of the dust and potential mold build-up will remain on the evaporator coil, and when the conditions are right, you’re likely to begin to smell that dirty sock odor in your home once again.

Apart from the smell, how do I know if I have a dirty evaporator coil?

Inside your air conditioner, there are two coils. One coil you can see, and one you can’t. Because you can’t see the evaporator coil on your indoor unit, it’s hard to know when it needs to be cleaned. So, how do you know if you have a dirty coil, apart from that dirty sock smell?

Ask yourself: Has your AC been experiencing frequent breakdowns? Have you noticed an increase in your energy bill, even though your usage hasn’t changed? Do you not change your filter monthly? If you answered yes to any of these questions, you might have a dirty coil. Once your AC system’s evaporator coil is back in working order, it’s important to take preventive measures that will keep “Dirty Sock Syndrome” from cropping up again down the road.

How to fix “Dirty Sock Syndrome”

The good news is there are steps you can take as a homeowner to help prevent, or at least minimize, “Dirty Sock Syndrome”. A clean house with a high quality filter system, changed regularly, is your first line of defense. Preventive measures include:

Check and clean your air filters regularly

One obvious area of potential concern in preventing “Dirty Sock Syndrome” is your filtration. Your air filter is the defense against dust that can wreak havoc on your AC system and cause “Dirty Sock Syndrome.” How long has it been since you changed your filter? A clean filter captures more dust and allows your system to push more air, which helps to prevent dust from collecting in trouble spots.

Be sure that you have an air filter in place

If your filter has become clogged with dust, you may be tempted to run your system without a filter until you can get a replacement. However, this can cause large amounts of dust to circulate through your HVAC system, causing problems that stretch far beyond a foul odor.

Schedule regular AC maintenance

Since “Dirty Sock Syndrome” is caused by a dirty evaporator coil, you’ll need to schedule an AC repair with an HVAC professional. This will involve either cleaning your AC system’s evaporator coil or replacing it, depending on how dirty the coil was. Note that if your AC system is still under warranty, your warranty may cover the installation of a new evaporator coil. Your HVAC contractor may also consider possible applications of sprays or other chemicals to your coil that can prevent airborne contaminants from establishing themselves within your unit.

Upgrade to a high performance filter

What quality of filter is in your AC system? Make sure you have a high performance air filter in your system. Consider an upgrade to a HEPA filter, which provides the most efficient filtration. A good filter will catch a lot of bacteria and mold spores, preventing their spread. However, that same high quality filter will not function properly if you go too long without replacing it.

Is “Dirty Sock Syndrome” harmful?

Dirty coils are not good for the health of your family or your unit. A foul-smelling system is indicative of other problems, ones that could affect the performance and longevity of your AC system. A dirty or clogged coil makes your air conditioner work harder to get the job done. This results in higher energy bills, more frequent breakdowns, and a shorter lifespan for your unit. So you might smell stale socks, but the bigger danger could be that you’re forced into a system replacement years before the expected replacement date. And throughout that time, your heating and cooling will be operating less efficiently, providing you with far less comfort and far higher energy usage.

“Dirty Sock Syndrome” is more than just a bad odor

It can also be dangerous to your home’s air quality. Your AC blows air into every room in your home, air that has passed over a dirty coil. If anyone in your family is experiencing flu-like symptoms or asthma, allergy symptoms or fatigue, it could be caused by mold in your AC or ductwork.

Mold can wreak havoc on human health. A 1999 Mayo Clinic study found that mold was the cause in nearly all chronic sinus infections. Other recent studies have implicated mold as a factor linked to a tripled asthma rate over the past 20 years. When mold and bacteria are free to circulate throughout your home, those with underlying conditions, allergies or sensitivities to mold may start experiencing symptoms:

• Nose and throat irritation
• Eye irritation
• Headaches
• Respiratory illnesses
• General fatigue

Mold and bacteria won’t cause all of these symptoms for everyone, but the smell alone is undeniably annoying and embarrassingly noticeable, and in a worse-case scenario can become health irritants.

Smelling dirty socks in your home? Contact the HVAC experts at Chas Roberts.

Hopefully this gives you an idea of why “Dirty Sock Syndrome” occurs and how it can be eliminated. You shouldn’t have to go another day with unwanted odors. Spare yourself from more headaches (and potentially higher electric bills and repair costs) down the road with the help of Chas Roberts.

Our team can help you fix and prevent “Dirty Sock Syndrome”. We will clean both coils to make sure your AC system is clean and running at peak efficiency. Contact us for a professional air conditioner tune-up, and kick those awful smells to the curb once and for all.