radiator

This creates what is effectively a radiator deep inside the earth’s hot, granite basement.

You may already have hung thicker curtains and blocked the drafts over the last couple of winters, but do not forget to switch off radiators in rooms you are not using and wrap up.

"I don't use it much and I only have one radiator on," she said.

Finally, a heat exchanger transfers this heat to water that gets pumped around your radiators, for instance.

"I live in a very old Guernsey cottage, which is stone and it's freezing in there in the winter, and I only run one radiator."