Ground Source Heat Pumps - Better Planet
Ground Source Heat Pumps

Ground Source Heat Pumps



Ground Source Heat Pumps collects thermal energy from the ground to produce hot water for heating and domestic hot water. The ground collector is in the form of horizontal loops, pipework buried in the ground at a depth of 1.2 meters or vertical boreholes with a depth of 80-150 meters. A system mainly consists of the heat pump unit, a hot water cylinder (connected to the hot water taps), a buffer tank (connected to the heating distribution), expansion vessels and the ground collector. The ground collector consists of the ground loops (horizontal or boreholes) a ground manifold and connecting pipework. The heat pump is located internally, in a weather protected space.

As with all types of heat pumps, it is important to specify the right size (kW) heat pump. For this, a room by room heat loss assessment of the property is required. A heat pump produces less hot water than a boiler and the lower temperature it can operate at, the more efficient the system is. Therefore, the overall efficiency of the heating system requires heating distribution (underfloor heating, radiators or fan coil units) which can deliver comfortable room temperatures at low operating temperatures. 

We are often asked about the difference between ground source and air source heat pumps. A ground source system is considerably more expensive than an air source one, but ground source is usually a better investment on the long term for the following reasons:

  • Ground source is more efficient than air source, as the ground is warmer than the air in the winter when most space heating if required. Both types of heat pumps use electricity, but an air source heat pump will use around 15% more electricity than ground source to produce the same heat.
  • The government tariff payments are significantly higher for ground source. A domestic ground source installation can get payments up to £34,000 over 7 years, while the maximum payment over 7 years for an air source installation is around £11,500.
  • The expected life of a ground source unit is 20 years, while the expected life of an air source heat pump is 15 years. A significant share of the cost for a ground source system is the ground collector. The ground collector will support many generations of heat pumps. It is an energy well which is likely to last for a very long time.