Dog vs Cat

[Catherine]

That brings you back to dwarf hamsters again. They are small and they don't need to much heat. I thought you might not have actual electricity.
You could put a hot water bottle under part of the cage or where ever would give the best heat. As long as the hamster had a choice it could keep warm if it needed to.

Are there heating pads that can be warmed and then left to cool. I have a heat bag I use for stiff muscles. It is actually rice in a cloth bag. I heat it in the microwave and it gives off heat for some time. It is safe because it gets cooler over time so it can't burn anything or over heat.
This might not be a good winter to get anything. I gather you have it cold.