When the heat comes up in my private house there is a fishy smell that permeates one of the bedrooms. Why?
My house is a cape cod style, with 2 bedrooms upstairs, when the central heating kicks in and starts blowing, the fishy smell is horrible in one of the upstairs bedrooms. I just changed the vents 1 month ago… what could it be.
You might have a dead animal (like a mouse) in the duct work. Decaying animals do tend to smell like that.