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BA I Aussen.jpg, class rooms before and after refurbishment, © Architekturbüro Haase, Karlstadt

Total refurbishment with high energy and spatial standards of the high school in Sonthofen at running school business. Integrated planning taking into consideration ecological and economic criteria such as energy saving, life cycle costs and the use of regional and sustainable construction materials. Reduction of follow-up costs and maintenance of the building value in the long term. Reduction of the use of fossil energies and of CO2 emissions of over 80%.

I Description of the measure

Schnittstelle.jpg, intersection old/new southern façade, © Architekturbüro Haase, Karlstadt

Title in original language: Nachhaltige Generalsanierung des Gymnasiums Sonthofen in Passivhausbauweise mit einer Einsparung von über 80 % CO2 im Vergleich zum Bestand’

Location of CNA: Germany

Municipality / regional entity: Sonthofen

Category of the experience: Measure
Type(s) of CNA:

Principal nomination: Technological
Secondary nomination(s): Other type: Environment protection

Thematic field(s):

Principal field: Buildings & construction

Spatial scale: Local
Time & duration:

Start date: Start of planification in August 2008, start of first construction phase in August 2009
Duration: 2,5 years for the construction works

Key word(s): Energy efficiency, refurbishment, school building


Total refurbishment of the high school in Sonthofen. Correct deficiencies in terms of safety, fire protection, construction physics, construction, lighting, room air, functional and spatial deficiencies and pollution with cold-mix foundation fibres. Carry out at running school business .a factor 10 total refurbishment with high energy and spatial standards. Integrated planning taking into consideration ecological and economic criteria such as energy saving, life cycle costs and the use of regional and sustainable construction materials. Reduction of follow-up costs and maintenance of the building value in the long term. Reduction of the use of fossil energies and of CO2 emissions of over 80%. Carry out an integrated planning involving the architect, all specialist planners and the school. Improvement of the learning environment for pupils. Transferability of the experiences to other school buildings of the same construction type.


A detailed analysis of the old construction materials (from 1972-74 ("Kasseler Modell") in precast concrete structure) was the basis of the integrated planning of the refurbishment. The specialist planners worked together within a consortium and the school was strongly involved during the planning work which considered ecological and economic topics. Life cycle costs of single construction parts were analysed in detail and special attention was paid to the use of regional and sustainable construction materials. In order to create an optimum learning environment sophisticated simulations of the ventilation and lighting technologies were carried out. The use of prefabricated components shortened the duration of the construction work. A continuous control of the refurbishment works in course ensured that the objectives could be met. After the finalisation of the refurbishment works a two years monitoring is set up to control and regulate the installation technologies.


If such a refurbishment is considered and planned in an integrated way it becomes obvious that refurbishments of existing buildings for more energy efficiency are worth the costs in the long term due to lower running costs. An important reduction of CO2 emissions could be reached through an effective refurbishment of the building envelope and the use of efficient environmental technologies at running school business. Attractive learning environments with a standard corresponding to a new building and with a high spatial quality for optimum learning conditions could be created. The re-use of existing construction material saved energy and costs compared to a new construction.

II Assessment criteria

Klaasenraum_2.jpg, class room, © Architekturbüro Haase, Karlstadt

Mitigation effects: Very high

CO2 emissions of the high school are reduced by more than 80% compared to the old building. This corresponds to a reduction of CO2 emissions of about 440 tons per year. An analysis of life cycle costs allows to reduce follow-up costs for single construction parts and a longer life time for certain parts. Through a longer life time material and energy can be saved. The re-use of the existing reinforced concrete structure also saved CO2, raw materials and energy which would have been emitted for the construction of a new building. A further reduction of CO2 and energy was reached by short transport distances for regional construction materials.

Impacts on adaptation: Neutral


Impacts on environment:

- Landscape: Positive
- Alpine ecosystems / biodiversity: Positive
- Water / soil / air: Positive
- "Other": None

Through the reduced energy use and CO2 emissions the refurbishment has a positive impact on the environment. The new wooden façade fits well to the typical regional way of construction. The use of water is reduced through urinals without water which saves natural resources.

Impacts on society:

- Social justice: Very positive
- Regional / cultural identity: Very positive
- "Other": None

Improvement of the learning environment for pupils. An optimum learning environment increases the learning motivation of pupils. A better education gives better opportunities for the future and often a higher social competence among pupils. The refurbished school acts as a model for other construction works and makes the school and the town of Sonthofen known in the region and beyond.

Impacts on economy:

- Employment / job creation: Positive
- Added value / income: Positive
- Know how / competitiveness: Positive
- "Other": None

Reduction of follow-up costs and maintenance of the building value in the long term. Through the involvement of local enterprises the measures contributes to maintaining and creating jobs in the region. The high school in Sonthofen can stand out in the comparison with other regional schools due to its high spatial and technological standards.

Public relations impact and awareness-raising: High

Regularly reports on the construction works and the experiences are provided to the funding institutions. The final reports are published. The school is presented to a wide public in the frame of many cross sectoral presentations. For interested persons from the region and beyond guided tours are regularly organised and accompanied by experts. This allows to explain details to visitors on site. The final reports, presentations and guided tours demonstrate to a wide public the potentials of an energetic total refurbishment and should provide experiences for upcoming similar refurbishment projects.

Transferability: Very high

The experiences can be transferred to other school buildings of the same construction type. One of the initial objectives of the refurbishment was to document the transferability of the experiences to other projects and to pass on the gained knowledge. The high school has been built from 1972 to 1974 in precast concrete structure according to the "Kasseler Modell". At the same time many schools of the same model have been constructed throughout Germany due to highly increasing pupil numbers. The experiences should become part of a guideline for refurbishments of these buildings.

Cross sectoral and integrative approach: Very high

The following aspects are the basis of an integrated planning approach wchich aimed at the highest possible reduction of energy use and CO2 emissions: - cross sectoral and active cooperation of the involved sectors, establishment of a planning consortium with all involved specialist planners. - Planning and modelling which respects sustainability criteria taking into account ecological and econimic aspects such as energy saving, life cycle costs and the use of sustainable construction materials from the region. - Strong involvement of the building owner (town of Sonthofen) and the user (planning team constituted of 5 teachers) for all decision making processes.

Good governance: Very high

The consortium (architect and all specialist planners) presented all proposals for decisions to the building owner and the user. The building owner took the final decisions. The involved construction authorities, funding institutions and the specialsts for technical supervisions are verified that all regulations and laws are respected and that funding is properly used. An external project manager supported the building owner with the controls of all construction steps.

III Executive body and contact information

Executive body: Administration, Universities or other educational institutions, Other public bodies, Individuals, Organizations of civil society, Private enterprises

Building owner town of Sonthofen, user high school Sonthofen Planning consortium: architect, and planners for electrical design, heating and ventilation, sanitation, statics, lighting Survey of construction works: involved construction authorities and technical inspection Funding: financial compensation Bavaria, Federal Environment Ministry, German Environment Foundation, German Energy Agency

Contact person(s):

Name: Dipl. Ing. (FH) Franz Friedberger
Institution: Stadt Sonthofen Abteilung Gebäudemanagment
Address: Rathausplatz 1 87527 Sonthofen
Phone: 08321/ 615-252
Fax: 08321/ 615-296
Email: [email protected]

Online information:

Online presentation of the refurbishment by the town of Sonthofen: Online presentation of the refurbishment by the German Environement Foundation:

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