My AC has started to turn on with the warm weather and with that I've been smelling a gross musty sour smell coming from the vents (only when it cools and not when heater is on). I last changed the air filter in January and had gotten all my AC ducts cleaned last fall. However, I had an AC Duct Cleaning company come today to inspect and the AC didn't smell anymore! That's so weird because it had been smelling bad the last 3 times it ran!
He said that if there is no smell anymore, then it isn't mold and was likely the smell of the condensation dripping from the piping so I don't need to do anything. He didn't even inspect anything because he said there'd be no point with no smell. He told me to not run the heater tonight and run the AC again tomorrow to see if there's a smell. If no smell, it's fine and if there is a smell, then they'd go in to clean it.
I wanted to get a second opinion on whether it's fine to just leave it if the smell magically disappeared or if I NEED to get the coils cleaned? I've called several AC companies and I get such different answers from each of them it's hard to know what is the "right" thing to do. One said to install an iWay filter into my unit, another said that I'd need my whole AC unit replaced.
Has anyone else encountered the musty smell going away on its own?