I have all kinds of heaters, the buddy heater included. They work fine at higher elevations anyways I've never hada problem. You need heaters for drying clothes and having a good comfortable evening. I spent muzzleloading season last year soaked to the bone everyday and so were the clients. Yeah we had waterproof gear but in those types of weather nothing stops the wetness. We used heaters alot, but I still will tell you honestly to buy a really good sleeping bag and turn off the heater while sleeping. We have atleast two tents in camp sleeping and eating tents. So you can leave your boots in the eating tent with the heaters running all night to dry them out and still wake up feeling good without being congested from the heaters. I wake up way before everyone else crawl out of my cold guide tent and go light the hunters heater so they have atleast an hour and half of heat before they get up. Plus it gives me time to feed the horses and saddle them. You could do the same thing by having the heater within arms reach and you could light it before getting up. But I won't sleep with a heater on. 1% or not I like the cold clean air of sleeping outdoors. And they make the bags that will do it.