I am not sure I am posting this in the right section-I was torn between basement, plumbing and heating. Here goes: I have had a terrible 'wet' or musty smell which comes and goes. I cannot determine a pattern. For the longest time I thought it was coming from my clay/dirt floor cellar because I had water problems down there; but I have fixed that last fall with proper guttering and even had a cement floor installed. It has remained dry. The winter was odorless and I thought the problem was solved, but it started again last spring/summer. I can smell it behind my washer, which is located in the kitchen and around the tub which is also off of the kitchen. (both rooms are above a crawl space) So maybe a plumbing issue? But the smell does NOT coincide with washing clothes or showering. Nor does it seem to matter if it's raining. In fact, the house can smell fine and then if I leave for a few days, it is rank when I return. It's been especially bad this past week-I could smell it very strongly at the cold air exchange in the livingroom (directly above the cement floor cellar) so I went in the cellar, where the furnace is located, and was surprised to feel warm tempertures when it should have been cool down there. I had the furnace running off and on for the past week. I thought maybe one of the duct things came loose and I was heating the cellar but I couldn't find it. I am having the furnace guy come next week for the annual inspect, so I'll ask him about it. And by the way, the furnace is less then a year old. So can anyone help me? Is it a plumbing, drain, or furnace problem? Why is the smell coming from the cold air exchange? Please help me, I am really sick of this stink!!!