250 year old house is heated using a heat pump

11/20/2020 | Print view

The house is almost 250 years old. But in terms of energy, it is state-of-the-art. - © Alpha Innotec — © Alpha Innotec

The house is almost 250 years old. But in terms of energy, it is state-of-the-art.

For a long time, heat pumps were not considered a solution for existing buildings. A building in North Rhine-Westphalia in western Germany proves the opposite. It won first prize in a competition organised by the German Heat Pump Association.

Germany will break through the one million mark of installed heat pumps this year. This is the prediction of the German Heat Pump Association (BWP). For this reason, the industry representatives announced a competition open to all homeowners who heat their building using a heat pump.

Heat pump also possible in old buildings

Now the winner has been determined. It is the owner of an 18th century brick building. After the house was renovated, the installers from the Krefeld installation company Lumitronic also brought the heating system up to the current state of the art. Now the owner of the two-storey building dating from 1771 in the small town of Wachtendonk, not far from the border with the Netherlands, heats with a heat pump from Alpha Innotec.

The installation of the underfloor heating was not so easy: The ceilings are low and have a limited load-bearing capacity.

It is one of the oldest buildings that still exists in the village. That impressed the jury. After all, for a long time heat pumps were not considered possible in the old building. The flow temperatures required for the old heating systems were too high. But through an energy-efficient renovation, a change in the layout of the interior rooms and, above all, the installation of underfloor heating, the heat pump can provide the energy required to heat the rooms.

Low ceilings were a challenge

The project was not easy to implement. The building had to be renovated in coordination with the heritage protection authorities. So the technicians had to make do without external insulation of the facade. Therefore, an internally applied layer of calcium silicate protects against heat loss. When laying the underfloor heating, the craftsmen had to cope with a very low residual load-bearing capacity of the wooden beam ceilings. It was not possible to reinforce them, as the ceilings are already very low. They therefore used a system with particularly thin heating layers. Together with the floor screed, this results in a very low installation height of only four centimetres.

Nothing to see here: The ground probe disappears under this nice piece of lawn.

A geothermal heat pump was installed as the heating system. With its 7.5 kilowatts of output, it provides enough energy to keep the interior comfortably warm and at the same time supply sufficient hot water. An integrated cooling function also ensures a pleasant climate in the rooms on hot summer days. "The house includes an inner courtyard, extremely narrow. This is where we were able to place the earth probe," remembers Ulrich Konen, managing director of Lumitronic. "That was almost millimetre precision work, but the people from our partner for the earth drilling are really good. Using a special drilling rig, they drilled two boreholes to a depth of 80 metres each.

Environmentally friendly heating at low cost

Now the approximately 250-year-old building meets the efficiency standard of KfW55. The homeowner is happy about the environmentally friendly heating system and low heating costs. "I heat the roughly 180 square metres of living space for less than 500 euros a year," she points out. (mfo)