I have been asked to come out and look at a home with a dirty sock smell coming from the HVAC. This is a home built in 2012. It is a ranch home with a finished basement. Supposedly it is a tight and energy efficient home that includes mechanical ventilation. The home does have a whole house dehumidifier that has been shut off and the smell still persists.

I assume that the coil is dirty and is a breeding ground for bacteria. One of the problems I have seen with drain pans is that they hold water, that is they don’t drain completely, To me it seems like a design flaw and the drain tube doesn’t sit low enough.

Are certain coils more prone to the dirty sock syndrome? Is there a permanent fix?

The homeowner was not able to provide much information on the mechanical ventilation. She didn’t know if it was a ERV or just air ducted to the trunk line. Is there ever a problem with an ERV/HRV contributing to the problem.