Like many “green” technologies, heat pumps are nothing new, but it is true to say that their popularity has increased dramatically in recent years.
You already have a heat pump, maybe more than one, in your house. A domestic fridge uses the heat pump principle to move heat into your kitchen, from the fridge, reducing the temperature inside, and warming the room, slightly.
Ground and water source heat pumps work on the same principle as your fridge, just on a different scale, moving heat from the earth, or water (surface or underground) into your house for heating water and the rooms. Heat pumps consume electricity, but they produce more watts of heat than they consume, so the efficiency is greater than 100%. This is usually expressed as Coefficient Of Performance (COP) and typical values are 3-4.
If you want to save carbon, you should really use electricity that has been generated in a sustainable way – e.g our special Greenenergy tariff
For ground source you need quite a large area of land, and you need to install pipes under the surface – about 1m down, so it will disturb your garden somewhat, or you can drill boreholes downwards, which can be rather expensive…
Financial payback can take quite a time, a recent EST research project found this could be up to 45years at todays energy prices, but we all know that tomorrows prices will be rather different!
Carbon savings, relative to oil, are good, though if you had access to gas, the savings would be rather more debatable.