I would like to insulate my whole-house fan in the winter. I've see insulating covers that you can attach with magnetic strips or velcro, but the look does not appeal to me and I don't trust how well a velcro seal would work (our fan is aluminum).
I'm curious if there are other ways to insulate a whole-house fan for the winter.
I had an idea to make a foam insert and drop it in from the top. I'm imagining spraying some expanding foam into a wood frame. The frame would rest on top of the frame around the hole for the fan. I could even mount it with some hinges so it's easy to open and close. Not sure how feasible this is.
edit: Checked the attic and saw that the fan motor extends pretty high. The insulation would need to be attached to the bottom of the fan opening. Looking like the cover might be my only option.