Erdwärme – wie funktioniert das eigentlich?

Heating our house with a heat pump

For 10 years we have been heating our house with a heat pump. It consists of a compressor that pumps a refrigerant  in a tube 90m down into the ground in front of our house which then heats the water for our floor heating. It provides a comfortable (steady) room temperature and climate.

The costs of the heat pump are high (we paid 10.000 € more than for a common heating system – which is about 50 % more than for a common heating in Germany). You also need a floor heating system but after the installation you only need electricity for the heat pump. So our ‘heating costs’ are 0 €, the electricity bill has increased but by now the investment has amortized.

One disadvantage that I do not want to keep back is that you cannot switch on the heating and have a warm room in a few minutes. So you must plan ahead a bit but as soon as the water in the floor heating is warm it is very pleasant.

At the bottom you will find some links in which everything is explained and shown in English.


The following article from a website in Canada explains how a heat pump works.

What Is a Heat Pump and How Does It Work?

A heat pump is an electrical device that extracts heat from one place and transfers it to another. The heat pump is not a new technology; it has been used […] around the world for decades. Refrigerators and air conditioners are both common examples of this technology.

Heat pumps transfer heat by circulating a substance called a refrigerant through a cycle of evaporation and condensation. A compressor pumps the refrigerant between two heat exchanger coils. In one coil, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings. The refrigerant is then compressed en route to the other coil, where it condenses at high pressure. At this point, it releases the heat it absorbed earlier in the cycle.

Figure 1: Gemeinfrei,

Refrigerators and air conditioners are both examples of heat pumps operating only in the cooling mode. A refrigerator is essentially an insulated box with a heat pump system connected to it. The evaporator coil is located inside the box, usually in the freezer compartment. Heat is absorbed from this location and transferred outside, usually behind or underneath the unit where the condenser coil is located. Similarly, an air conditioner transfers heat from inside a house to the outdoors.

The heat pump cycle is fully reversible, and heat pumps can provide year-round climate control for your home – heating in winter and cooling and dehumidifying in summer. Since the ground and air outside always contain some heat, a heat pump can supply heat to a house even on cold winter days. In fact, air at –18°C contains about 85 percent of the heat it contained at 21°C.

Ground-source (also called earth-energy, geothermal, geoexchange) heat pumps, which draw heat from the ground or ground water, are becoming more widely used, […]



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