Indeed Domeguy, that's the most efficient way. Would be great to have something like an attic hatch that would let the hot air naturally rise to for easy removal, but I'm good so long as the power is on.

Helomech, I must confess that part of my being able to handle the cold is the humidity is very low here in winter; without moisture the cold just doesn't penetrate clothes and it is radically easier to dress for vs. a humid area. Visited Houston months ago and knew to expect the effect, but still got chilled at 15C/59F; here that is ideal hiking weather! At 15% humidity you can deal with -40C provided there isn't a wind (rare to have wind at this temp here). After living in this climate for my life to this point my body is adapted to cold, but that also means I suffer in the heat.