I used a Primus Micron at 7500 ft at about 15F with a full small Snow Peak canister and it worked fine for heating water for tea and soup. Not sure how it would have fared if I had run it close to empty. I set it on a piece of blue closed cell foam cut from the familiar foam sleeping pad everyone seems to have had at one time or another. I could see ice forming on the canister as it cooled off while running.