Ogilvie - I just have it turned down quite low, but have it on all the time, not just at night time. Mind you we don't get the really low temps that you have south - -3 for us the other night was quite low. I've got the large one (at work so can't remember which one, but its red!). You do need to trim the wick a bit and light it with the wick quite high, but then once the flame has taken just reduce the wick until you end up with just a nice glow. My greenhouse doesn't smell at all (just me!) and I certainly can't smell it outside.

Hope this helps. Good luck!