Air Conditioning Stink? It Might Be Dirty Sock Syndrome

Man pinching his nose due to a bad smell

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You took out the trash.

You cleaned the garbage disposal.

You cleaned the litter box and bathed the dog.

You sniff-checked the washing machine.

The smell is lingering, and you can’t miss it when you come home.

Chances are, your HVAC system has dirty sock syndrome.

A stinky air conditioner isn’t just a nuisance. Mold and bacteria growth are dangerous if left untreated—especially for people with respiratory disorders or compromised immune systems. 

Don’t worry. You can keep your home’s indoor air quality clean and prevent the problem from happening again in the first place. Here’s how to fix dirty sock syndrome:

What is Dirty Sock Syndrome?

Air conditioner outside of a home

Have you ever wondered why dirty socks or gym clothes become so foul-smelling? 

When we sweat, bacteria linger in the organic material of our clothing. Eventually, mold and mildew start growing, and you notice that ever-familiar unpleasant odor. 

In the case of your air conditioning, mold, bacteria, and mildew have grown on the dirty evaporator coils. Bacteria and mold need special conditions to grow, and HVAC units provide the perfect place: It’s dark, and there’s plenty of moisture. 

Also, when dust and dirt accumulate on the wet evaporator coil, bacteria have a friendly food source. 

That offensive smell is what we call dirty sock syndrome. You might notice it more often in the spring and fall when you aren’t running your HVAC as often. If you run a heat pump HVAC system, your HVAC system is also more susceptible to mold spores. With a gas furnace, the intense heat is usually enough to destroy any bacteria or mildew before it has a chance to enter your home.

Air conditioners are also more at risk of mold growth because there’s no heat to kill any growing microorganisms. 

While we call it “dirty sock syndrome,” this doesn’t necessarily mean that your heating and cooling system smells like dirty socks. Your home might smell like must, dirt, or just plain “off.” You’re most likely to notice a foul smell upon returning home.

Is Dirty Sock Syndrome Dangerous?

Dirty sock syndrome isn’t necessarily dangerous, but it’s also not healthy.

According to the EPA, Americans spend an estimated 90% of their day inside. When we think of pollution, we tend to think of car exhaust and smog. However, the EPA says pollution levels are up to 5x higher indoors than outside. 

While stinky air conditioning may not necessarily expose you to elevated levels of mold or bacteria, it could cause problems for certain people, such as:

  • People with compromised immune systems from cancer or HIV
  • People with asthma
  • People with chronic health conditions
  • Young children
  • Elderly residents
  • People with respiratory problems

As COVID-19 spreads in the United States and California, protecting at-risk groups from unnecessary respiratory stress is imperative. 

The bottom line is it’s crucial to take dirty sock syndrome seriously.

How Can You Fix Your Stinky Air Conditioner?

A woman holding her nose from something stinking.

In most cases, your evaporator coil might need a good scrub. Cleaning evaporator coils isn’t a job you want to do yourself because it involves opening up your unit and messing with electronic parts. Call your local HVAC technician for a thorough evaporator coil and duct cleaning.

Even if you manage to cut off the power and scrape off some of the gunk, you won’t be able to give your evaporator coil the thorough cleaning it needs to eliminate the smell.

Instead, call in the experts at Home Comfort USA. We offer a 32-Point Tune-Up where we run through every potential issue, check for faulty parts, replace your filter, and give your unit the cleaning it deserves.

Unfortunately, if the problem has progressed, you might need a new evaporator coil. We can help you investigate your warranty if that’s the case. If your HVAC is still under warranty, this could reduce the cost drastically. 

That’s why you must call us as soon as you notice the smell of dirty sock syndrome. If we can get to the problem quickly, it can save you money by avoiding emergency repairs. 

How Can You Avoid Dirty Sock Syndrome in the First Place?

Once your evaporator coil is cleaned up or replaced, you’ll want to adopt preventative measures to prevent dirty sock syndrome from returning.

Use a High-Quality Filter and Replace It Often

Polyester and pleated air filters are your best choice for removing pollutants and allergens from your home’s precious air. Most people tend to use fiberglass because they’re cheaper, but you’ll pay for it later with poor air quality and HVAC repair costs.

You’ll also want to replace your air filter regularly to keep your home healthy and hygienic:

  • Every 90 days for pet-free homes if no family members have allergies
  • Every 60 days for homes with one pet
  • Every 30 days for homes with two pets or a family member with respiratory or immune system problems

If your home is particularly humid and mildew or mold is common, err on the side of caution and replace your filter in 30- or 60-day increments.

Clean Your Ductwork 

Once bacteria, mold, and mildew have had a chance to grow on your evaporator coil, it spreads spores and debris into your ductwork. 

Our expert technicians at Home Comfort USA can thoroughly clean your ductwork and seal up any leaks to moisture, so mildew never has a chance to accumulate or spread.

Schedule Regular HVAC Maintenance Visits

A 32-Point Tune-Up every six or 12 months—depending on your unit, usage, and needs—can help us stop more significant problems before they happen. 

It’s much easier and less costly for us to clean your evaporator coils and replace small faulty parts rather than waiting for major problems to arise.

Install UV Lights

UV lights aren’t the best choice for every system. However, if you live in an area where humidity levels are naturally high and dirty sock syndrome is a chronic problem, they may be worth considering. 

Small UV lights shine onto your evaporator coils and kill any microbes before they have a chance to grow and reproduce.

Call the Comfort Guys—We’re There!

Don’t wait for that stench to get worse. Once bacteria and mold start to grow, homeowners deal with it entirely, and it won’t get better on its own.

Schedule a maintenance check or 32-Point Tune-Up from Home Comfort USA, or call 888-462-0089!

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