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Why Your Air Conditioning System Smells Bad The First Time That You Use It Each Year


April 1, 2016


Each spring we get a number of calls from customers asking us why their air conditioner smells bad the first time that they turn it on.

A smelly first use of your home’s AC is common, and HVAC technicians sometimes refer to this early season air conditioner smell as ‘Dirty Sock Syndrome’.

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Why does your AC smell musty when first turned on?

During the winter months when your AC sits dormant, dirt, dust, and debris build up on its coils and filter. Over time, this buildup turns into mold and mildew, and that mold and mildew creates the musty smell that spreads throughout your home when the air conditioner is turned on for the first time. The smell isn’t the only thing that is being spread throughout your home – the mold spores travel with it.

How can I prevent my AC from smelling musty?

There are a couple of steps to prevent “dirty sock syndrome” from affecting your home this spring.

Change your air conditioner’s filter.
Your air conditioner has likely been collecting dirt and debris since its last use. A new and clean AC filter will eliminate the smell from the mold and mildew that has grown on last year’s filter and will also provide your home with cleaner air…all while keeping your air conditioner running more efficiently.

Have your air conditioner’s coils cleaned.
Just like the system’s filter, the coils collect dirt and debris that turns into mold and mildew during the winter months. A coil cleaning should be performed by an HVAC professional, and it is usually included in annual maintenance.

Call us in New Jersey to book your annual maintenance before you turn on your home’s air conditioning unit for the first time. We’ll eliminate the musty air conditioner smell while prepping it for a season of efficient service!

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