In article IVIuh.1059$Pk5.452@trndny04, says...

Our bathroom has a ceiling fan/light combination that lets in one hell of a
draft. During our saga about the leaking bathroom roof (resolved, it
seems, finally), I got a look at the construction, and the exhaust fan
shunts the air through something that looks a bit like a dryer hose, to a
circular exterior port on the house. That port is hooded, and there is some
kind of apparently useless circular "flap" that does very little to keep
cold (!!! it was 20 below last night) air out of the bathroom.

If you wizards can suggest a way to solve this, other than only showering in
the summer, I would be eternally grateful.

Donna


There should be a flap both at the fan and the hood, and together they work OK.
But here is an inline vent blocker you can add:

http://www.batticdoor.com/bathfandraftblocker.html


--
Dennis