Why does the house smell when the central air runs

It almost sounds like the start to a joke, doesn’t it?

Well, when I run the central air in my house, it gives the house a musty smell. It’s noticable enough that when you come in from outside, you say “jeesh, it kinda smells in here.” 10 minutes later you don’t notice it anymore. You can smell it coming through the vents…it’s definitely related to the AC.

Some other background info:

There is no smell at all when the heat runs, this is strictly an AC phenomenon.

The AC was serviced/recharged last summer. I don’t remember a smell last summer, but my wife ASSURES me that the smell was there too.

We run 2 dehumidifiers in the basement and empty them daily.

We have not had the ducts cleaned recently.

So, what do you all think? TIme for a service call, a duct cleaning, or both??

Get the a-coil /ducts/blower cleaned. It should be cleaned every 2-3 years. You may have mold/bacteria on the coil. Very common with pets in the house..

Hi, Just trying to be helpful here. Here are some thoughts. We built a new home in Rochester in ’67. Never had a problem this was a story and 3/4 (full dormer accross the back). We retired and built a new rambler in Plainview that is a look out rambler. In other words basement windows above ground but no walk out. We decided to put in an air exchanger even though it was not code at that time. Last year for the first time I did not run the air exchanger in the summer period because my thought was that with air exchanging from the windows it would be o.k.. Well for the first time we had musty smell last summer. So I will run the air exchanger this year unless the central air is on which would be counter productive. Good luck and I hope this might help you.

Brooktrout, you run 2 dehumidifiers in the basement ? Sounds like you could use an Easy Breathe ventilation unit. We installed one in our house about 4 months ago, got rid of the dehumidifier and the air is noticibly cleaner smelling and dry. Dehumidies really suck the elctricity too.

big g

I see you are from the Eau Claire area. PM me with your number and I can have someone I took apprenticeship classes with help you out, he lives up your way. Maybe clean the coil and put some pan tablets in.

Make sure your drain is draining properly too

Speaking of drains. Make sure your floor drain isnt dried up and releasing sewer gas. Check any other traps you may have as well and fill them with water.

Thanks for all the input guys! Looks like a good cleaning of the system and the ducts is the first order of business.

This is what I would do