Our environment is a gigantic energy reservoir even in winter and during periods with little sunshine. Even at low outside tempera-tures, the soil, ground water and air still contain sufficient heat to be used for heating purposes. Heat pumps can tap these energy sources for the heating and hot water system.
A geothermal pump heating system is already installed in every other new single-family home built in Switzerland. These sys-tems already account for a market share of 90 % in the Swedish market. The number of heating and hot water heat pumps in-stalled in Germany has also increased strongly in recent years and now accounts for a market share of 15 % in new single-family and duplex homes.
Aside from these markets, however, heat pump technology is still relatively unknown in Europe and is only just being disco-vered as an eco-friendly and efficient means of producing heat.

Although the first heat pumps were developed in the mid-19th century, the basis for a competitive technology was only esta-blished towards the end of the 20th century as energy resources declined and product quality improved significantly.
A heat pump operates on the same principle as a refrigerator, but the other way round. The fridge extracts heat from the food-stuffs and delivers it to the surroundings; a heat pump extracts heat from the soil, ground water or air and makes it available for use in heating the buildings and domestic water. It operates most efficiently: only one kilowatt-hour (kWh) of electricity is needed to drive the heat pump and generate between three and four kilowatt-hours of thermal energy.

A distinction is made between geothermal, ground water and air heat pumps, depending on the heat source used. Geothermal heat exchangers are used in 56 % of all new pumps installed in private residential construction in Europe. These may take the form of earth probes vertically installed in a drill hole or horizon-tally installed earth collectors. Earth probes offer the advantages of reliability, compactness and a very large seasonal per-formance factor.
Ground collectors also ensure a sufficiently large seasonal performance factor for the heat pump, but they require more space as the area cannot be built over.

Ground water and the surrounding air can similarly be used as sources of heat. Ground water can be tapped via combined suction and force wells, while the surrounding air is tapped via air ducts or the free intake of air. Combined suction and force wells require little installation space and ensure high seasonal performance factors, while the air as heat source requires the least space and lowest investment costs, but also yields the lowest seasonal performance factor.

In addition to being relatively independent of rises in fuel prices, planning reliability, a long service life and low emissions make the heat pump an attractive alternative to conventional heating systems. The higher investment costs as compared with most other heating systems are compensated by low, virtually con-stant operating costs over the years.

Together with high cost-efficiency and the additional possible uses of new product generations, basic political conditions and state aid programs once again play a decisive part in determin-ing the market success of this eco-friendly technology.
All in all, 242,000 heat pumps were installed throughout Europe in 2006 – and the trend is definitely upwards.