By sucking 55-degree heat out of the ground and concentrating it, the heat pump is able to deliver 110-degree heat into the warm air ducts of a central heating system.

FORBES: Underground Cash

The fund gives a grant for a package of energy efficiency and heating measures ranging from insulation to, in some cases, a central heating system if you do not have one at the moment.

BBC: Battling bills - what help is there?

We had reported earlier in the year that the chapel had originally opened in 1811, but was now threatened with closure because it needed a bit of tlc in the form of a new fire escape, a new boiler and a central heating system which could ward off the oncoming winter.

BBC: Lancashire - A visit to Dalehead Chapel

The next stage is to link this exchanger to a district-heating system so that it can be pumped into central heating.

ECONOMIST: Monitor