during last century final decade i spend few weeks in a place called Khairpur Tamiwali @sheran it is close to border with India, we can hear & see ( with binoculars ) thick smoke for arriving & departing train to a town on other side in distance. It was mid november and temp during day was in single digit dropping to negative after sunset.
In the tent sleeping bags were rolled up at 4 pm (to stay hot) while wide spread in open to absorb maximum heat ( & disinfect ) during sunlight.
2 warm water bottles were inserted on either side of sleeping bag before 5 kg LEHAAF is to be pulled up. We used full sleeved thermals with hoods to slip into bed.
the best part is in case of PEE during the night we need to bring out the warm water bottle out of bed & tent to perform ritual
so to keep utility bills down use warm clothes & stay warm in heavy blankets
during the summers i was in the same area for a summer task and explored the ' Pakistani airspace flight path from pacific to europe flights '