The heat source for this system is a borehole with a length of 300m. It is filled with water only. The heating circuit is operated without buffer storage. The DHW cicuit contains a DHW storage. Due to higher inlet temperatures in the brine circuit and underfloor heating which can be operated with low inlet temperatures, good preconditions for the heat pump are created.   

Efficiency values of 5.1 in 2010 are far above the average of 3.9 for ground source heat pumps. This results from low temperatures in the heating circuit and very high temperatures in the brine circuit in winter. The water pump's share of 3 % on the total electrical energy demand is below the average of 6 % which has a positive effect on the SPF. In 2010 the share of DHW of 5 % was below the average of 18 % and further increases efficiency.