I was tired of going to bed all sweaty so this is what I came up.   It worked well on my deer hunt last Nov/Dec when the air temperature was cold at night. Buddy heater , PVC shower frame, shower curtain & rings, masonry mixing tub & a bug sprayer with kitchen sink sprayer attached. Crank up the Buddy Heater in the tent and heat up the water on the stove. It was nice going from a warm shower to a warm tent. The tent is a 10x14 Kodiak Canvas.   Probably just use the sprayer outside of the tent when the air temp is warmer in Sept. Sprayer also works great on dishes. Cheap, reliable & effective.