Geothermal Heat Pumps are also called ground source heat pumps and can be used for space and water heating. They use the ambient heat of the earth beneath the surface which is between 11°C and 13°C in Ireland.

By using a compressor, heat pumps can boost heat at a low temperature and release it at a higher temperature so that it can be used to heat the house. For every unit of electricity used to pump the heat, 3-4 units of heat are produced, leading to much reduced fuel bills and carbon emmisions.

These systems are most efficient when used in conjunction with underfloor heating in suspended timber floors as they are more responsive.

The good news is that is is generally feasible to install a geothermal system in an existing house even in a housing estate.

A grant is available for these systems from SEI for €3,500. See Greener Homes Scheme for more information.

There are 2 options –

• A horizontal system uses pipes that are laid flat over a large area under the ground.
• A vertical system uses pipes which are inserted into a deep bore hole.

In the case of an existing house in a housing estate a vertical system is more suitable due to space constraints.

The vertical system requires drilling at least one 150m hole which is then plumbed to the heating units and heating system (these details should be advised by your installer). The bore hole can be in the front or back garden.



Note: If you are installing solar water heating and a geothermal heat pump, it is a very good idea to integrate the systems as it will give good gains in efficiency.