SRS: You could have a small propane heater on hand for outages in the GH! Out of the house, the fumes would not do harm. On Whidbey, I bought a "Mr Buddy" (I think). and used it in the greenhouse turned pottery studio. The info said "No fumes"; there were. I phoned tech support and was told to return it for a replacement. No fumes! Worked wonderfully well. Wish I had remembered that when you were cold in Texas! Even if you had to let some fresh air in, it would have kept you warmer.