It must be nice to have enough power to be able to do that. When I'm off grid and on solar I don't, so I can't. Even if I did, I wouldn't. Irons, space heaters, hair dryers, electric water heaters, slow cookers, crock pots and electric hot plates are all things I will never use if I am on solar power. Creating heat with electricity is the most power expensive thing you can do. The only other thing I can think of that might take more power is driving machinery such as: refrigerators/freezers, air conditioning, power tools and air compressors. If I am going to create heat while camping I use my propane stove. If I was in a situation where I had to heat a bed, (someone suffering from hypothermia), I would do what my grand parents did, use a hot water bottle. Fill a Nalgene bottle with hot water. Enclose it in a scarf or a hat so it isn't so hot it will burn. Place the bottle under the covers. I haven't needed to do that, if I'm lucky I never will. In the mean time, my body generates enough heat, I use wool and space blankets to keep it around.