A simple $2 stovetop model of sand battery heater
Two pet bowls, stainless steel, one inverted on the other, the bottom has sand, the top has holes drilled on the top, held together with a paper clip. Sand can be heated on stove or fire pit, before being placed in the room to be heated atop the tealight candle stand.
Sand can store 600 Celsius of heat which is an enormous amount, the stove boils water in a few minutes that is 100 Celsius, with a few more minutes you are going above that, enough to heat a small area. Should reduce heating cost by a lot over winter
When it comes to people complaining of the cold, or “feeling cold” they’re generally complaining of cold in their fingers and toes.
The core is generally easy to keep warm as long as you’re fed, dry, clothed and out of the wind.
Maybe cover supplements and herbs or anything that increases circulation to the digits. That would be extremely helpful.