I am trying to help someone problem solve and over heated 2nd story here in Portland, OR. This person has central A/C, but doesn't like using it and it doesn't effectively cool the 2nd floor as well. The house has vaulted ceilings, which makes adding a 2nd floor return in the ceiling cost prohibitive.

The client is open to a wall mounted fan. Given that we live in a heating climate, does anyone know of an insulated wall mounted fan that would work for this application (2x6 walls).

Any other bright ideas?