I have 2 separate furnaces, one for basement suite and another one for upstairs. The tenant in basement suite smokes and I smell the cigarette smoke upstairs through the vents... how is that possible if we are supposed to have to different air systems? I asked the technician, he said we are sharing the return air vent, what the heck!! My question: is it possible to have 2 different air return vents? how the tenant in the basement suite can have his/her own air system without sharing?
Thank you.