Usually turn the temp to its lowest setting and crawl in my 25f sleeping bag. That is when I'm by myself, when DW is along, flannel sheets with a very comfy comforter with temp set around 55-60f.
We set the thermostat at 60 degrees and we use two comforters. With 100 watts of solar and two battery's we have camped like this for 2 weeks no problems.
We frequently dry camp when the low temps hit the 20's or 30's. We use flannel sheets which make a huge difference in sleeping comfort. We run the heater at 65 degrees before we go to bed, then shut it off when we crawl in. I usually get up first and turn the heater back on in the morning before the DW gets up for her coffee.