the image brought to mind is one from a lodge where the gas burners
on the cooking stove have large inverted flower pots (ceramic) to radiate the heat given off..
this is sometimes done to heat rooms in places where the propane
supply in large enought to allow it. I wonder if there are any
fumes to worry about with this method?

sometimes a brick heated in or on a fireplace or woodstove
can be wrapped in layers of paper and or cloth and placed
under the covers to warm the feet of the bed. or a hot
water bottle or even a tightly sealed qt. or gallon juice bottle.

there are antique bed warmers that use cherry pits to hold the warmth
and long-handled pans that are rubbed between the blankets to take the chill off of the bed. should this be in the getting ready for winter thread?