Buildings

Freiburg, Germany

Cutting home energy consumption by 80%

Summary

Freiburg’s energy efficient housing standard has lead to reductions of up to 80% in average household energy consumption. Moreover, the standard has influenced the development of two attractive districts - Vauban and Rieselfeld - that are setting new standards for energy-efficient housing in Europe. Low energy housing in Vauban is estimated to reduce CO2 emissions by 2100 tonnes per year in 150 residences.

What is it?

Introduced in 1992, the “Low-energy Housing Construction” standard was incorporated into all lease and purchase contracts for City property and stated that no more than 65 kWh/m2 of energy may be used for heating purposes in households. Following amendments to national legislation, the standard has subsequently been revised to ensure that Freiburg remains at the forefront of low-energy development in Germany.

The standard is not a building ordinance, but a matter of civil law applying to public land that is sold by the city to private investors. Freiburg has pursued a programme of retro-fitting old buildings with renovations and upgrades, and all new housing stock must meet the low-energy design standards. The Vauban and Rieselfeld districts are large-scale showcases of Freiburg’s achievements.

How does it work?

Contractors are obliged to build according to low-energy guidelines, to orient buildings so that they optimise their capacity for use of passive solar energy, and to make roofing available for solar collectors. Lease and bills of sale contain rulings that specify about 5,000 m2 must be kept clear for solar collectors, yielding around a 40% reduction in the use of warm water in new districts.

The entire Vauban and Rieselfeld districts have been constructed to this 65kWh/m2 standard, comprising a population of 18,000 people. Around 150 units have been constructed to “passive house” (15kWh/m2) or “plus energy” (houses producing energy surpluses) standards, savings around 2100 tonnes of CO2 each year. Additional energy for passive houses is required for only a few weeks each year – a wood chip biomass combined heat and power (CHP) plant provides this energy.

The integrated design concept of the Vauban district also means that a traffic concept has been development, leading to reduced use of private vehicles; the number of solar installations is constantly increasing; and rainwater is collected (for example, for use in school toilets). A biogas plant has also been introduced to the district. Freiburg has achieved high-quality housing for young families, with green spaces and good social infrastructure, whilst reducing energy consumption and CO2 emissions.

Annual savings and C02 reductions

Low-energy housing costs around 7% more to build than traditional housing, yet energy consumption falls by up to 80% and CO2 emissions are reduced by 30%. Consumption of oil for heating purposes is more than halved, from 12-15 litres to 6.5 litres per square metre heated. The rising price of oil means low-energy housing is even more effective and the houses in Vauban save residents €1,000 a year per dwelling.

Annual savings of 1,900 litres are heating oil in a single family home are achieved and emission reductions are: 6,5 kg sulphur dioxide (SO2); 3,4 kg nitrogen; 3,1 kg carbon; 0,3 kg hydrocarbons; and 001, kg dust. Around 2100 tonnes CO2 equivalent are reduced by the passive housing development.

Costs

Construction costs for multi-unit buildings are lower. Costs associated with energy efficient construction are initially added directly to the purchase price, but the public has accepted these additional costs, in the anticipation of reduced running costs. Costs associated with new local government buildings are of course paid by the municipality.

Next steps

• continuous environmental improvement
• policy integration and an inter-sectoral approach
• self-commitment of the municipality to the principles of sustainable development
• contribute to conserving natural resources
• contribute to preventing global warming
• contribute to making energy use sustainable
• contribute to providing affordable, environmentally friendly, socially compatible housing

Application

There has been wide public acceptance of this programme with significant interest throughout Germany and other European countries. Dozens of cities have indicated interest in implementing a similar programme.

An important element of success in the implementation of a programme aimed at low-energy housing construction is to have building contractors and architects accept the programme. This requires keeping these people well informed and overcoming the stereotyped view that low-energy construction involves increased financial burdens.

The programme has also benefited from making use of an existing resource pool of architects and administrative officials from other communities who are implementing similar programmes. For instance, creative examples of low-energy housing construction in Scandinavia demonstrated to local architects lead to the result that this type of construction created new opportunities in housing design in the city of Freiburg.