In my experience.. temps in teens snowing and windy. 18" lite cylinder stove with seasoned oak cut to length and split the stove would keep it comfortable inside a floorless luxe octopeak throughout the night but would be out by morning, often sleeping with my bag open, in baselayers with a poncho liner as an extra insurance blanket inside the bag. I sleep on a coleman cot with 2 pads (steal the one from my 2nd cot when its just me camping) and I put down a quilt or two under my bag. I found that if I had good tinder, it was a breeze to quickly fire up in the morning. If I wanted to cook on it, it was better to have some pine to get a hot enough blaze as the oak was more of a long term heat source. Also keeping the dampers wide open was somewhat a necessity to keep the burn going strong.