Cut your water-heating bill by two-thirds with our recommended model of heat-pump water heater.

A heat-pump water heater extracts heat from the outside air and shifts it into your hot water. It's claimed it can do this much more cheaply than heating the water with a conventional electric element.

That's the hype. In one of the first tests anywhere, we tested 6 to find out how efficient they were. The results were revealing - particularly at lower "winter" temperatures. To get the hoped for savings, you need to choose your model carefully and for the appropriate climate zone.