[Moth]

I think you are getting turbulence from having the make up air behind the torch and too close to the vent but that's just what I see in my head without a real pic of your set up.

You wouldn't have to open that window very much at all to get a good draw. When you say it's causing a draft when you try it...did you block off the fresh air intake behind the torch when you gave the window a try? If you opened the window, turned on the fan AND left that intake open it wouldn't give you a true result. It would actually be worse.

As far as heating goes, I live in a cold area, too. The trick is to heat yourself, not the room. Radiant heat will warm you and you won't waste energy trying to heat the air. Something as simple as clamp lights with heat bulbs got me through my first winter but there are lots of nicer radiant options.