What is a ground source heat pump?

Ground source heat pumps use pipes buried between one and two metres deep in the garden to take heat from the ground. The temperature of the ground remains a fairly constant 10-13°C at this level, irrespective of the season. A water glycol (antifreeze) mixture is pumped through these pipes and heat from the ground is transfeered to the liquid. A temperature increase of the ground loop fluid of just 3 or 4°C, is all the heat pump requires.

The returning warmed liquid is fed into a heat exchanger / evaporator. which is concentrated in a heat pump and used to warm water for radiators or underfloor heating systems. It can also be used to pre-heat water before it goes into a more conventional boiler.

The length of the pipe buried will be determined by the size of your home and the amount of energy you require to extract - the longer the length of pipe, the more heat can be taken.

The loop can be buried horizontally (as shown) or, if there is a shortage of garden space, a vertical loop can be installed to a depth of up to 100 metres.

Costs of installation

A typical system has prices ranging from about £7,000 to £13,000.

Running costs for a year, where all hot water and space heating can be provided by the system are likely to be around £650 per year, but will depend on a number of factors - including the size of your home, how well insulated it is and whether you are using it in conjunction with other green energies such as solar panels.

Grants are available for installation.

Once only of interest to a small minority, green is the new black as far as self-building is concerned.

With the effects of global warming becoming increasingly apparent, more and more people are seeking greener ways to provide the energy needed to run a home.

Whether it's solar panels, heat pumps, high specification glazing or eco-friendly wool insulation in the loft space, there is little doubt that it is self-builders who are setting the standards for a greener future for the building industry and the way we live our lives.

Underfloor heating for example, has been available for years but, by and large, the self build market has been the industry's bread and butter - with large scale property developers still opting for standard, less efficient radiators.

But it's not all about saving the planet. Incorporating green ideas into a home can lead to reduced running costs and save you money in the medium to long term too. And when you come to sell your home in the future, you can guarantee that the greener it is the more attractive it will be to prospective buyers.

There is a greater sense of purpose from the government to promote green alternatives too with a stick and carrot approach in place.

Building regulations now demand far better energy efficiency while government grants are available for loft insulation right through to solar panels, heat pumps, wind turbines and other microgeneration technologies.

Self-builders are leading the way as far as greener homes are concerned and greenselfbuild.co.uk will be with you every step of the way towards a greener future for you, your family and the wider community.