Energy efficient retrofit of a nursing home in Stuttgart - The German BRITA in PuBs demonstration building

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One of the 8 demonstration buildings out of the EU 6FP ecobuildings project BRITA in PuBs was the renovation of the nursing home Filderhof in Stuttgart, Germany. The aim of all demo projects was to reduce the primary energy consumption by factor 2 and at the same time increase the user satisfaction in the building also by factor 2 due to the retrofit. The building was renovated and enlarged by an extension in 2004. A new heating plant (combined heat and power unit in combination with solar thermal and photovolatics) and an energy improvement of the building envelope (windows, walls, roofs, cellar ceilings) were realised. A new lighting system was installed as well. Before the retrofit the total primary energy consumption was 396.8 kWh/m²a, after the retrofit 97.2 kWh/m²a resulting in a primary energy saving of 299.6 kWh/m²a. The investment costs of € 924,222 for the energy efficient measures led to a payback time of 20 years. The user questionnaire showed that the user satisfaction is very good after the retrofit.

Acronym of the case


Author(s) information


Heike Erhorn


Fraunhofer Institute for Building Physics, Stuttgart, Germany


Lessons learnt

Main lessons learned: - With this project it was shown, that it is possible to reduce the primary energy of existing buildings by over 50 % - The minimized energy consumption can be supplied with renewable energy in the order of 22 %. - Architectural aspects (influences) may have a strong influence into the retrofit concept even if a building is not listed. In the case of Filderhof an external insulation could not be realised. An internal insulation on the external walls was advised. This led to less energy savings and results in more planning work on details in order to prevent thermal bridges. - Economic influences may change the material used for building parts. At Filderhof, the glazed atria roof has now only small skylights. The architects had to react on the situation and transferred the planned PV system to the opaque roof parts. This had a positive effect on the energy savings and the gains of the PV system. - The use of rooms in the cellar has to be carefully planned in order to keep the heated zone as compact as possible. However, the given situation and necessary functions of rooms may be more important for the building owner than the energy efficiency. - There is a lot of coordination work to be done with several partners of the project inside the city and especially with financial government. Thus the project time enlarges to five years from the earliest planning phase up to the end. - The combination of a retrofit with the construction of a new building makes sense for the improvement of the situation in an old nursing home. Therewith an efficient and innovative system may be applied, which wouldn’t be realised in this scale if only the retrofit had be done. - It is necessary that the operation staffs are trained in energy efficiency. It has to be explained to them, when a special operation is necessary for the economical run of the system. This concerns also the substitution staff as was realised when the CHP in the Filderhof lied idle for a longer time while the main staff was away. - If the retrofit of an old building is combined with the construction of a new building, the calculation of retrofit costs and energy savings is very complicated. Also the separate estimation of costs for the old building is difficult as there are many costs belonging to the old building but occurred by the addition of the new building.

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Start date - End date

Monday, 5 January, 2004 to Wednesday, 30 April, 2008

Source of funding


Funding description

EU 6th Framework Programme