Heidelberg „Residential neighbourhood "Blaue Heimat" “

Context

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The residential neighbourhood Blaue Heimat is located in the Handschuhsheim urban district in Heidelberg (pop. approx. 145,000). A total of 155 apartments and ten semi-detached houses were built between 1927 and 1951. Over time, the entire building stock, notably the building services, became obsolete. The insufficient heat insulation led to high running costs, the insufficient fire and noise insulation led to further limits in the housing quality. Because of the partial lack of bathrooms and the distribution of space, the layout of the apartments no longer corresponded to today's needs.

Project description

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The aims of the redevelopment, which started in August 2004, were to remove the structural and space-related drawbacks and the creation of a climate-neutral building complex without use-related (CO2) emissions. The focus of the energetic redevelopment was the toughening of the building shell, replacement of the building technology with energy-saving components and the installation of a ventilation system with heat recovery. Layouts were changed in the buildings, and the living space was expanded with comfort-forming elements (e.g. balcony). The building section (55 units) was completed in October 2005.

For the redevelopment, the partly empty buildings were completely vacated by the landlords’ relocation management. The tenants had the opportunity to return to the complex's apartments after the redevelopment. After redevelopment, the gross rent was based on the rent level for the urban district. The basic rent is higher than for comparable living space, but the lower running costs have a permanent, cost-reducing effect. Since the redevelopment, there is a great demand for living space in the Blaue Heimat according to the housing company. The tenants assess the quality of life there very positively.

The planned energy savings were achieved in the first two years after the modernisation of the building. The primary energy use (heating and electricity) fell from 438 kWh/m² per year to just 100 kWh/m² per year. The annual heating requirement, in particular, was reduced as a result of the measures taken by 87% to around 21 kWh/m² per year. However, excessive ventilation heating loss has been identified because tenants continue to open the windows despite the technical ventilation system. This is why the housing company offers training and events regarding the building technology. This provides the tenants with information about the features of their apartments and the consequences of their actions. Heat loss has been restricted as a result. Apart from the behaviour regarding apartment ventilation, the building technology does not place any particular requirements on the residents.

The entire building complex has been certified as a "ZeroHaus" (Zero Building) in a multi-stage certification process. The process is based on the evaluation of the overall consideration of the energy saving directive. Based on this, it demands even more challenging limits. Apart from observing the energy limits, the certification includes monitoring the planning and redevelopment measures.

Project chronology

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Year	Event
2003/04	Planning for the redevelopment measures
2004	Start of comprehensive modernisation work
2005	Completion of the modernisation work
2005	Provisional certification as a ZeroHAUS
2006	Interim audit for ZeroHAUS certification
2007	Final certification as a ZeroHAUS

Aims

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• To reduce the primary energy requirement by 80 %
• To standardise the apartment structure
• To create new layouts and new apartment types
• To improve the apartment quality
• To increase the living space by extending into the attic and adding balconies

Types of measures

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• Roof, ceiling and external wall insulation
• Installation of triple glazing
• Enlargement of the window spaces facing south
• New construction of balconies thermally separated from the building (south side)
• Installation of a block heat and power plant
• Individually operable ventilation system with heat recovery
• Hot water connection for dishwashers and washing machines
• Drying rooms with efficient ventilation
• Integration of regenerative energies by installing photovoltaic modules
• Extensive information to the tenants about the energy-saving use of the technology

Innovations

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As a result of the interaction of building insulation, innovative building technology and other energy-saving possibilities, the annual heating energy requirement fell to just approx. 21 kwh/m². This is considerably below the threshold for new buildings according to the energy saving directive. Moreover, the need for (system-related) electricity has been reduced by around 60% to approx. 50 kWh/m² per year. The remaining energy required is provided by a wind power provider from regenerative sources. Overall, there is CO2 neutrality Overall, a groundbreaking project for saving energy and reducing CO2 for multi-storey old buildings has been realised.

Sources

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• <http://www.ggh-heidelberg.de> Internet presentation, flyer and brochure about the project
• Interview with the project initiator, on-site visit

Further information

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• Low-energy houses in the existing stock <http://www.zukunft-haus.info/de/projekte/niedrigenergiehaus-im-bestand.html>
• ZeroHaus certification, <http://www.zero-haus.de/>

The project location can be directly translated into Google-maps. Project in Google-Maps

The projekt site ist to be found at postal code: 69121 - town: Heidelberg - street: Karl-Philipp-Fohr-Straße 4-10.

Protagonists

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• Gesellschaft für Grund- und Hausbesitz mbH, Bluntschlistrasse 14, 69115 Heidelberg, Tel.: (06221) 5305-0, Fax: (06221) 5305-111, Email: <info@ggh-heidelberg.de>, Web: <http://www.ggh-heidelberg.de>
• Solares Bauen GmbH, Emmy-Noether-Str. 2, 79110 Freiburg i. Br., Tel.: (0761) 45688-30, Fax: (0761) 45688-50, Email: <info@solares-bauen.de>, Web: <http://www.solares-bauen.de>
• Stadt Heidelberg, Amt für Umweltschutz, Gewerbeaufsicht und Energie, Prinz-Carl, Kornmarkt 1, 69117 Heidelberg, Tel.: (06221) 58-18000 and 58-18010, Fax: (06221) 58-18290, Email: <umweltamt.heidelberg@heidelberg.de>
• Architekturbüro Johannes Gerstner, Theaterstrasse 7, 69117 Heidelberg, Tel.: (06221) 163505, Fax: (06221) 168694, Email: <info@gerstner-architekten.de>, Web: <http://www.gerstner-architekten.de>
• Cischek Ingenieure GmbH, Tullastrasse 19, 69126 Heidelberg, Tel.: (06221) 301866, Fax: (06221) 302618, Email: <heidelberg@cischek.de>, Web: <http://www.cischek.de/>