A geothermal installation offers not only the possibility of heating in wintertime, but also of cooling in summer. Using the so called Natural Cooling the compressor is turned off while the brine takes the heat from the house and transports it into the soil. By doing so, the fluid in the collector cools down and can now flow back into the building and continue to withdraw heat from the environment. The required power is minimal and comparable to some bulbs. The Active Cooling requires the performance of the compressor: in this manner the system works more effectively and reaches lower temperatures, which makes it possible to cool even by using fan coils.