How well does that work, exactly? I've never tried (and living in Florida, I don't get the chance much anymore <img src="/images/graemlins/smile.gif" alt="" /> )

How much of a temperature rise can you expect from a single candle? Seems like cracking the window enough to prevent CO buildup would let in so much cold air it wouldn't be worth doing. Obviously, I'm wrong, just curious if anyone's actually tried this...

I guess you'd want a can or something in which to burn the candle. And it seems like this would have some of the same precautionary warnings that having a flame in a tent would have.