Imagine a personal heating system that works indoors as well as outdoors, can be taken anywhere, requires little energy, and is independent of any infrastructure. It exists – and is hundreds of years old.
Hot water bottles provide warmth for a lot longer than 1 hour. The trick is managing the heat flow with insulation – if you’re using an uninsulated hot water bottle radiating its heat into the air around you then you’re using it wrong.
A hot water bottle wrapped in a wool cover and kept against your body under your blankets will keep the chill off you all night.
Hot water bottles provide warmth for a lot longer than 1 hour. The trick is managing the heat flow with insulation – if you’re using an uninsulated hot water bottle radiating its heat into the air around you then you’re using it wrong.
A hot water bottle wrapped in a wool cover and kept against your body under your blankets will keep the chill off you all night.