Originally Posted by NCPatrick
I'm thinking of using a nalgene flask
as a hot water bottle. Seems like a flat flask type bottle would work fairly well for hot water bottle use.
worth a try.
It will definitely cool off faster...less volume to begin with, and more surface area for that volume. I'd think about carrying one of those around if needed during the day, and go with the bigger mass of a 32 oz bottle at night.