We just moved into a house that smells bad when ac runs. We cleaned the coils and cleaned and bleached the pan. The smell is still there. We had the ducts professional cleaned. Smell is still there.

I recently walked by a flower garden that was being watered. It had the same smell as my house but fainter. It smelled metallic. I realize that it does smell metallic.

Before we moved in, a plumber fixed a leak in a sewer pipe.

It doesn't stink in the morning when the ac runs. It only starts stinking when it gets hot outside in the afternoon. On cooler days, it doesn't stink in the hottest part of the day when the ac is running.

We think the house was bug bombed before we moved in and we bug bomed it after we moved in.

The furnace in the house is vented from underneath the house, but it doesn't smell bad under the house. The smell is definitely coming from the cooling air registers.

Please help. The stink wakes me up at night.

T.K.

Do a search for Dirty Sock Syndrome or Musty Coil Syndrome. This problem is most often found in heat pumps.

You say that the furnace is vented from underneath the house, does this furnace draw the return air from under the house (some older homes did this) and does your condensate drain under the house or is it piped to the outside? Mike

Do a search for Dirty Sock Syndrome or Musty Coil Syndrome. This problem is most often found in heat pumps.


No worries, my husband is an ex-electrician and building inspector. As I said in the question, we cleaned the coils and cleaned/sanitized drain pan. It's not Dirty Sock and Musty Coil Syndrome.

Is this unit mounted horizontaly under the house? If so then may be it is leaking water into the insulation in the coil area.

Is this a heat pump system with electric auxiliary? This may be a reach, but I encountered this situation once: homeowner complaining of occasional odor & not cooling well. The problem? Defrost thermostat (in outdoor unit) was stuck closed, so every 90 minutes the system was initiating a defrost cycle & turning on auxiliary heater. Oh yeah, and there was this other little thing: a dead & well-done rodent in the auxiliary heater strings! One other thing to check: condensate drainpipe. If it is tied into a sanitary sewer line and/or does not have a trap, EEEWWW!

I think I would focus on AC coil in duct... Sounds like you only have it when AC is

Running... There should be a drip pan under coil to catch condensation and runs it

To a drain... Sounds like drain is plugged and forcing water to leak inside furnace

Which dampens dust bunnies, ever smell wet bunnies, mold, etc

Hope I helped you get a good nights sleep...

When I turn my ac unit on it smell like someone has used da bathroom I had a plumber 2 check my pipes and clean my spetic tank and I still smell it what can I do