[Arcturius]

Unfortunately, with the large surface area you'd have in a giant trash can, despite it's poor thermal conductivity, would probably release heat to the room about as fast as any reasonable peltier could take it in.

Unless, of course, you stuck your res. somewhere else, like the bathtub, so you've got a nice, steamy bath drawn anytime you want it, and the heat is in a room elsewhere.

Or, you could just run your waterlines to your parents room with a radiator, and make sure the hot air hits your mom's side of the bed. (women are always cold, after all)