I purchased my first wood stove back in November, a Sirocco 30, and have a question regarding smoke/vapor. Somewhere I read that you know the cat is working properly if there's no smoke coming out the chimney. Aside from a glowing cat at times, I also noticed there was no smoke exiting the chimney when the temperature was around freezing. (This was when the stat was about halfway). However now, with temperatures at -30 to -40 C, I notice smoke exiting the chimney (stat is at about 75%). Or is this just water vapor? Obviously there will be some heat escaping the chimney, which would explain it, but curious as to how much smoke the cat cleans up.