Ground source heat pumps (GSHP) extract heat stored in the earth's crust to heat homes and water, reducing carbon footprints and heating bills. There are three main components: 1) A ground loop of pipes buried horizontally or vertically to absorb heat from the ground. 2) A heat pump that uses an evaporator to absorb heat and a compressor and condenser to transfer it for heating. 3) A heat distribution system of radiators or underfloor pipes to provide heat to rooms and hot water. GSHPs are most effective when homes are well insulated, and grants are available from the Sustainable Energy Authority of Ireland to help with installation costs.