I tried for the first time tonight the advice occasionally recommended here of putting a small fan on the floor of the doorway to blow the colder air out of my office back into the warm front room where the woodstove is, and man, does that ever work! Only took about 10 minutes for a real difference in air temp around my chilly feet. Trying to blow warm air into the colder room had little effect, but pushing the cold air out really does work to bring the warm air in.