We are having a huge odor problem, only when our air is on. We have had the coils replaced all filters, the ducts cleaned and cannot find the source of the odor. We have only been in the house for 5 months, this started about 2 months ago, the septic system has been cleaned in the last 12 months.

Does anyone have any ideas what in the world this could be, it is so embarrassing when people drop by and just frustrating not being able to find the source and eliminate it.

Please Help!! :eek:

Start by checking all return air duct. Usually the return duct creates a negative pressure in the structure and can cause the problem you have.

One other area is the air condition drain line. Depending upon how it is run it can pick up odors from the sewer.

Many years ago I had a situation with a customer that took me a whole day to figure out. When the home was built they cut off a plumbing vent near a return joint in the basement. You could not see it unless you were really looking for it. Once fixed all was OK.

NowI am sure you have heard of the dirty sock syndrome before since you kind of have it. It seems like you have already taken many steps to correct. Good hunting.

There is another possible answer to your problem that you may not want to hear... you could have a dead animal in the duct work ( feed and/or return )... such as a mouse. I have seen it on a number of occasions. You may have to hire a duct cleaning company that has a camera system to check all of your ducts...