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What is Dirty Sock Syndrome?

The term “Dirty Sock Syndrome” is used to describe an occurrence wherein a cooling and heating system releases an unpleasant, musty odor that is similar to the smell of dirty socks. The smell is milder cases might be like the dusty odor released when the air conditioner is first switched on after a long time of being not in use. It is most noticeable at the time the unit kicks on. The good news is that there are many air conditioner hacks you can use to easily get rid of this problem.

Air Conditioner Hacks


Causes of Dirty Sock Syndrome 

The Dirty Sock Syndrome problem begins when the indoor evaporator coil of an air conditioner is damp and cool, allowing microorganisms to grow there. The microbial sludge dries out when you shift to heating during fall. As the temperature goes lower at some point, your HVAC system will perform a defrost cycle amidst stages of heating. 

It is this changing back and forth from cooling to heating that causes the bacterial slime and mold to produce a stink. This can also take place during spring when you shift from heating in the late evening and early morning to cooling in the afternoon.

You may notice that the odor goes away as you operate the HVAC system on cooling alone or heating alone for a long time, but that does not mean that the issue is fixed. If the HVAC system always releases unpleasant smells, particularly on heating mode, the issue is not Dirty Sock Syndrome.

Dirty Sock Syndrome can occur in all kinds of cooling and heating systems that feature evaporator coils, though it is most prevalent in heat pump systems. The heat produced in a gas furnace system is commonly strong enough to kill microbes. 

Ways of Getting Rid Easily of Dirty Sock Syndrome

Before treating your air conditioner for this Dirty Sock Syndrome, you need to make sure that it is really the problem you’re facing. Foul smells can come from several sources, so check your unit for another possible cause using the different air conditioner hacks below. 

One of the air conditioner hacks to consider in getting rid of this problem easily is emptying the air conditioner’s drain pan beneath the indoor evaporator coil to inspect for any clogs. The condensate drain line is not clogged if the small amount of water that you pour drains away. Otherwise, you will have to utilize a wet-vac for removing the blockage through the outdoor cleanout line.

Air Conditioner Hacks


Lines connect to your plumbing systems can begin smelling when p-traps have already worn out. Insects and dead rodents are also possible sources of odors. You may check the accessible portions of the ducting system for unsealed or loose joints between metal duct sections, flex duct tears, and open-end ducts emptying into open spaces like wall chases. These can draw smells into your rooms from the walls, basement, and attic.

If the air filter of your air conditioner is wet. There is a moisture issue that could also be the source of noticeable odors. A block AC filter can also contribute to these odors. So you need to change the filter base on the directions of the manufacturer. In most houses, a regular fiberglass filter must be replace once in three months. 

Also Read: Going Ductless vs Central Aircon Systems

Cleaning the evaporator coil is also one of the air conditioner hacks in getting rid of the issue. A mild case might be treat by cleaning the evaporator on your own with a foaming coil cleaner. You need to call a professional for a more thorough cleaning of the coil. If this does not fix the problem. It might be necessary to purchase a new evaporator coil for serious cases. 

When your coil is already clean and your home smelling fresh anew, several preventative air conditioner hacks can reduce the risk of recurring odors. These steps are beneficial to your entire HVAC system, making them worth the investment. You need to regularly check how well the condensate drain of your AC functions. If it often clogs or does not drain well, it might be worn out and need to be replace.

Contact an HVAC professional and schedule an aircon inspection. Most only require cleaning once in five to ten years because duct systems that are install properly collect little debris. However, there is always a chance an issue like a water leak. Rodent infestation could arise and start producing foul odors. This inspection will determine if your ducts are responsible for the foul odors of the entire system. Whether they must be clean or not.

It is unpleasant to know that your air conditioning unit is releasing the odor of dirty socks to your home. But, the issue is rarely severe. A thorough cleaning is an air conditioner hack that can solve most dirty sock syndrome cases. Getting the problem address as soon as possible keeps microorganisms from developing through the HVAC system. Turning into a much bigger problem. When the foul odors go away, take steps to get rid of any growth of bacteria or mold in your home’s HVAC system. Make sure to have a monthly checkup with your local aircon service provider

Author Biography:

Ossian Rey is a passionate writer of SOServices ( and an expert in Maintenance Service relate articles. Loves to play video games and chit-chat.