I lived in a van in Anchorage, Alaska for 6 years, and I used both an Olympian Wave 3 and Wave 6. At normal winter temps I used just the Wave 3, in the teens I turned it off and used just the Wave 6, and below zero I used them both at the same time on low. When it got down to -30 below zero I had them both on high. <br /><br />The Olympian is a true catalytic heater while the Mr. Buddy is not. It is much safer! Catalytic is a chemical process (no flame) so it produces virtually no carbon monoxide. I turned my Olympians on in October, and they ran 24/7 till April. The only time I turned them off is when I changed or refilled the bottles. <br /><br />I personally would not run a MR. Buddy while I slept, although I have friends who do and think it is safe. In normal climates, the Mr. Buddy works fine--I have one now. But Olympian is a better, safer heater. Bob