I'm in a condo with neighbors on both sides. utility closet is in the basement.
It smells like old stale cigarette smoke in my utility closet, like somebody has been smoking cigarettes in there for years almost.
I'm not a smoker, and I noticed a faint smell of cigarettes in the past but thought it came from neighbors outside. I've been working from home during the pandemic and realized the smell is definitely coming from the utility closet after following my nose (sniffing all around the house lol) to the source. I don't smell it anywhere else in the house or from any of the ducts. It's just inside of the utility closet really. There's a hot water heater, the air handling fan/heater/evaporator unit, and circuit box in the utility closet.
Also, when I first moved in 2 years ago I never noticed the smell in the utility closet.
I'm not 100% sure, but it almost seems like the smell comes when the heat turns on. Is this possible?
Could the smell come from one of those? or could it be from the neighbors through a hole in the wall somewhere? If it's from a neighbor, how can I find and plug the holes?