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The domestic heat pump experiment

Rostock, Germany
Energy-efficient building at its finest
The domestic heat pump experiment
The domestic heat pump experiment
The domestic heat pump experiment
The domestic heat pump experiment
The domestic heat pump experiment
The domestic heat pump experiment

In Rostock, in the far north of Germany, an exceptional experiment was initiated. Building energy consultant Günter Oldigs, who concentrates on the energy efficiency of buildings for more than 20 years now, set himself an ambitious goal - to switch to a completely renewable heat supply for his own house. As an experienced player in the energy game, Mr. Oldigs took it upon himself to plan and implement a fully geothermal-based heating system. In order to ensure a full-proof system at minimal hassle, Thermaflex’ simple, yet reliable plug & play distribution system could accommodate.

The heat supply of this low-energy home, which was built in 1994, would switch from a fossil fuel oil-based-heating system to an air-water pump in September 2014. The 110m² living space of is completely facilitated with floor heating. Previously, the house was supplied by an oil-fired low-temperature boiler with a 15 kW capacity. The potable warm water was supplied from a domestic hot water storage of 200 litres. Nowadays, an air-water heat pump with 9kW does the same job. To create a connection from the heat pump to the heating system of the house, an integrated solution using our pre-insulated Flexalen plug & play set was found.


To achieve optimal efficiency, a well-insulated system flow and return system was crucial. Insulating the return flow of a ground-sourced heat pump can already reduce heat loss up to 77%.
Mr. Oldigs, who breathe a passion for smart, and sustainable energy solutions, quickly opted to secure his heat distribution with Flexalen. The bottom-line of this self-experiment was sustainable efficiency, leading to characterize also the materials used for this project. The premise of this project was to limit the CO2-emissions caused by the oil-based energy supply in combination with resource protection through the transition to renewable energy.

„If you were to ask me if the environmental consciousness plays a significant role within the decision making process for the implementation of a heat pump, I would fully agree on that! As a building energy consultant, I wanted to set an example. Thus I decided for the installation of an air-water heat pump, as there was not enough space for a ground collector. The heat pump is working perfectly, free of any maintenance, and very silent since implementation.“ Günter Oldigs, GEBGO


The transition of the heat supply to renewable sources with an air-water heat pump demonstrated impressive results, and shows how anyone can make the switch while saving significant costs on their energy bill.

The connection of the heatpump was realized with our Flexalen 600 Plug & Play set. The transition from the old heat supply to a renewable-based one with the installation of a Flexalen system went smoothly, and ended in great enthusiasm by all contributing parties.

„The Flexalen 600 Plug & Play Set is especially recommendable for such applications, as the pipe comes with all the accessories in one handy carton. I’m looking forward to further projects of this kind with Flexalen 600 from Thermaflex.“ Günter Oldigs, GEBGO

This far-reaching impact on people, planet, and prosperity further carried Mister Oldigs to extend his renewable energy supply with the installation of a photovoltaic system in 2015. As a result, the primary energy savings are at 70% now, and his total CO2-emissions cut by 71%. This makes this self-experiment an absolute frontrunner in low-scale energy-efficient building.

The development of the heating energy consumption, the annual COP as well as the efficient integration of the photovoltaic system can be tracked on the Website of GEBGO.


GEBGO (building energy consultant)

Multitherm Montage GmbH / Bentwisch (heatpump installation)

  • 75 % of end energy demand
  • reduced what results in
  • 49 % total energy savings
  • thus
  • 51 % CO2 are saved
  • safeguarded by a
  • 100 % reliable supply
  • since project completion
1 month
Michael Biewald
Technical advisor
Sub.: Thermaflex Germany
Rostock, Germany
0066dda5 7659 4da3 830a 743637e5af6a

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  Successful in the past - prepared for the future (PBPSA) PDF 1619 KB Preview Download Mail

This brochure is giving an introduction to Polybutene including a review of the performance of Polybutene pressure piping systems in meeting the needs of sustainable building regulations.

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