"IT'S like a fridge that acts in reverse," is how Alan Bolton explains the workings of his air-source heat pump.

Where a fridge takes air and squeezes the heat out of it to keep things cool, the pump takes air and extracts the heat from it to keep homes warm.

Mr Bolton of Grange Park, St Arvans, said: "It's a very efficient system and its very cost effective."

For every unit of electricity it takes to run the pump, it produces three units of energy.

He said: "In a village like St Arvans which does not have mains gas, the savings are massive in terms of your central heating and it also provides a constant heat.

"It's not just about economics, the impact on the enviroment is a lot less too."

The house is also fitted with solar panels.