We use the propane heaters in our box blinds and it's never bothered the deer any. We also use isopropol alchohol and a roll of toilet paper in a paint can that doesn't seem to bother deer any. Again , our heaters are in box blinds , if your hunting treestands I'd concentrate on warm clothing (layers , and wind proof) , hand warmers , and a full face knit stocking cap. Wool is great for cold weather. Put your primary focus on keeping your head , neck , feet , and hands warm. Anything that cuts wind is a must for late season hunting.

Good luck!

<---Doug---<<<