How Do I Get My AC to Stop Smelling Musty?


The air conditioning in your home shouldn’t smell musty when you turn it on during a hot day. However, there are reasons why there’s an unpleasant smell coming out of the unit. Fortunately, there are various methods out there to address the issue.

Why is my AC smelling musty?

There are three main reasons for this phenomenon. You either have a blocked drain line, the AC is too large for your home, or the evaporator coils have become filthy over time. To remove the unwelcome smell, follow these steps:

Change the air filters

Dirty air filters can result in bacteria and mold growth. Air conditioners are cold, and the filters are the perfect environment for bacteria and mold to thrive. To fix this, you should clean or replace the air filters. Air filters are cheap and readily available. It also only takes a few minutes to replace them and get rid of the foul odors.

Clean the evaporator coils

The evaporator coils in the AC units outside are exposed to moisture and low temperatures, which provides a great place for mold and bacteria to breed. To properly clean the coils, use a disinfectant, cleaning agent, or bleach. Chemicals will kill most of the harmful microbes and prevent them from growing. Regular cleaning will keep your AC free of the musty smell.

Clean the condensate line

Condensate lines are pipes connected to the AC unit outside. They serve to drain the water that forms when the AC is on. Unfortunately, the condensate lines are ideal breeding grounds for algae, bacteria, fungi, and mold like the evaporator coils. Sometimes, small plants grow in and clog the condensate line. The blockage can lead to even more musty smells and severe damage if the homeowner ignores it.

To clean the condensate line, pour vinegar or specialized cleaning solution and wash it thoroughly. Doing so once every 30 days is enough to prevent excessive blockages and microorganism growth.

Wipe the indoor AC

It’s not enough to replace the air filters, as the bacteria and mold spores are possibly still inside the unit. The best way to prevent the musty smell from returning is to wipe down the interior unit with antimicrobial cleaners. Be sure to let it dry before reassembly.

Regular cleaning can prevent AC units from smelling bad, but often it’s better to ask for expert help. You can call a professional HVAC cleaning service to ensure a thorough clean. Say goodbye to the foul odors and enjoy the cool benefits of an AC on a hot day.


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