We have lived in this duplex townhouse for over 10 years. It is relatively "new" in that it was built less than 15 years ago. We have gas/ forced air furnace. While we have been stable tenants, next door has seen many come and go. About 6 months ago a family moved in and they are heavy smokers (we don't smoke). They moved in in the summer, and from time to time we would seem to get a whiff of what seemed to be stale cigarette smoke. We attributed it to both of us having windows open. Soon it became apparent that even with the windows closed, on hot days with the AC on, and in the fall and now winter, we routinely get the smell of a day old ash tray that appears to be coming from our cold air return ducts. The landlord has been more than willing to help us, but since he has a bad sense of smell, he doesn't smell it. Both my wife, myself, and my four adult daughters smell it easily. Even one of the landlord's buddies was able to detect the smell of it coming from the cold air return. The odor comes and goes on a daily basis. We've even peeled back some some of the duct work near the adjoining wall, and indeed there appears to be no connection between the two units. Since the landlord can't smell it, he is thinking that it can not be the cigarettes, but something else. To us it is undoubtedly the odor of an old ashtray.(as opposed to smoke directly from a burning cigarette). We don't believe any of the previous tenants smoked, and it is difficult to believe this may be just a coincidence. We replaced the furnace filter three months ago with a hypoallergenic filter, and in checking it out it too seems to contain the same stale cigarette smell, although not as strong as the one that permeates the house. My wife is allergic to cigarette smoke and this occasionally gives her migranes. We've even looked into moving but love the location and the value (if it wasn't for the smell) of our dwelling.

Could it be something other than the cigarette smoking neighbors? We'd love to solve this problem short of moving. The landlord is willing to pay for a furnace and duct cleaning, and we are can easily change the filter but thinking we should wait until the furnace and duct cleaning has occurred. We did have the ducts cleaned about three years ago. Please help.

You can clean the ducts but the problem might not go away. There are always nooks and crannies that air can flow through in the type of units you live in. usually this smell shows up when you have a negative pressure in your home that allows the odor to be drawn in. (Like you running a bath fan or range hood) or when your neighbors area produces higher air pressure than your unit.

The real cure for this is to run a duct to the outside from your return air. This will keep your area under positive pressure and prevent the migration of someone else's odors. Every time your blower runs it will draw in fresh outside air and pressurize your unit keeping the smell out. That is just about the only cure I can think of for you in the situation you have. Note: the size of the duct does not have to be that large but a local HVAC company THAT KNOWS what they are doing can calculate and do the install for you. Good luck.