Freiburg:
Low-energy Housing Construction Project
Freiburg:
| |
| Country: | a) Western Europe | ,b) Germany |
| Language: | |
| Type: | Project, 2 |
| Area: | City/Town, 100,000 - 1 mill. |
| Actors: | Local government |
| Funding: | Local government |
| Topics: | Air-quality |
| Climate protection | |
| Energy | |
| Housing (and new settlements) | |
| Information and public participation | |
| Land use and -planning | |
| Objectives: | Improve access to information |
| Improve environmental efficiency | |
| Improve intersectoral cooperation | |
| Increase public awareness | |
| Increase use of clean technology | |
| Increase use of ecological building materials | |
| Increase use of renewable resources | |
| Reduce energy consumption | |
| Instruments: |
The project "Low-energy Housing Construction" launched by the city of Freiburg has established new, energy-efficient housing construction standards which are incorporated into all lease and purchase contracts for City property. This is an example of how a municipality can use its established legal powers for effective environmental management. Freiburg's innovative example stands out for several reasons:
Freiburg city, with 191.600 inhabitants and covering an area of 153 km2, has a budget of US $ 567,000,000 as its disposition. In the course of the housing situation in Freiburg (mainly old, no insulation and admitting draughts) and a potential heating reduction of 80% with improved insulation, the project intends to facilitate the reduction of household energy consumption and related emissions affecting climatic change. In June 1992, the City Council passed a new policy calling for the reduction of household energy consumption. The new energy code states that no more than 65 kw/m2 of energy may be used for heating purposes. Application of this standard would reduce the consumption of oil for heating purposes from 12-15 litres to 6.5 litres per square metre heated.
The city has made low-energy housing the norm for construction of new houses. Only low-energy houses can be built in areas where the City Council has jurisdiction. This includes buildings that are financed by the Council or buildings on Council leased or sold land. The effect of this policy will be especially felt in the case of large scale developments where the Council writes a low-energy standard into new lease and purchase contracts. The terms of the contract state that 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. This would yield about a 40% reduction in the use of warm water in new districts.
The marginal costs associated with low-energy construction amount to 3-8% of total investment paid by the builder or the buyer. These costs are regained in energy cost savings. The following example for a single detached family home for a period of one year. In multi-unit buildings the additional construction costs are lower.
Annual savings and emission reductions in a single family home per year are as follows:
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 stereotype 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 led to the result that this type of construction created new opportunities in housing design in the city of Freiburg.
Cost associated with energy efficient construction are initially added directly to the purchase price. The public has accepted these additional costs. Costs associated with new local government buildings are of course paid by the municipality. This workload of this project requires two full-time employees.
Freiburg i. Brsg., den 29.05.2000
BVA / Geschäftsstelle Rieselfeld
Frau Lorenz / Telefon 201 - 4095
Experience report of low energy house building corresponding to the Freiburg standard in the district “Rieselfeld“.
In the mean time the low energy standard is a normal technical standard for building apartment houses. The efforts of the city office Rieselfeld referring to information, advice and controlling have good results.
In 1999 there were 10 apartment houses examined by an extern engineering office and other 27 terrace houses examined by the city office Rieselfeld. Until the end of April 2000 the city office Rieselfeld examined the way of calculation of 12 other terrace houses and 2 apartment houses.
Because of the current presence in the territory we achieved early contact with the architects and planning engineers and so we could give same advice of planning and it was possible to correct some constructions in time.
The following text gives a short result of the examinations.
Apartment houses
In commission of the city office Rieselfeld an extern engineering office examined - after the first part of examination 1996/1997 (17 houses) - a second set of 10 buildings in cooperation with the city office Rieselfeld in 1998/1999. (At present the examination of 9 houses is completed.)
On this occasion compared with the first house group, a clear improvement becomes apparent in regard of the observance of the energy characteristic value. The most frequent mistakes and difficulties didn’t depend on the policy of calculation, but on the lack of exactness of calculating the certificate and also not knowing technical rules.
The self-control of the technical construction is almost only practised by bigger firms and also there it is not always complete. The product information, who has to bee at the building site according to the legal rules, are regularly not available.
Because of the experience of the first examinations 1996/1997, the first of July 1998 the city inserted into the contracts of purchase, that the mathematically certificate has to be examined by a legal examiner before the beginning of building the house and also that the realised construction has to be examined of corresponding to the mathematical certificate.
Independent of the examinations done by the extern engineering office we can say that the instrument of the legal examiner charged by the building owner shows only limited effects until now.
Indeed meanwhile the examination of the mathematically certification goes quite good, but in most cases the finishing supervisor report is only produced after the written request of the city office Rieselfeld or can’t be produced, because there is only a limited respectively no supervising.
Summing up it may be said, that there is a positive development in range of apartment house buildings. The already 9 completed examinations of the second house group show a mean value of 64,6 kWh/m²a. This result shows, that when there is a respective control, the Freiburg standard of low-energy-house is really observed.
We mainly lead this positive development back because of the fact, that the architects and planners know, that we control the production of the certificates and that the city office of Rieselfeld makes local spot checks to control the realised construction.
We think, that because of that controling and the urgent instruction during the sale conversation to use this offer, the advice of the city office Rieselfeld for building owners and planners is already more often used.
Family houses
The situation of family houses is different. Terrace houses and here especially end houses turned out to have difficulties in observing the limit value of energy used for heating purpose. Since November 1998 there have been built 93 terrace- and double-houses. The city office Rieselfeld examined 27 Of these buildings but only 4 houses could be checked at building site, because of lack of personal capacity.
The low-energy-house-standard of Freiburg, in regard of the demand level, turns out to be difficult for terrace houses and mainly for terrace-end-houses and it shows that it is linked with more technical expenditure than for an apartment house. Moreover family houses, in contrast to apartment houses, are less technically planned. Come up to the wishes of the building owner the planning will be modified (f. e. larger windows) without checking the consequences to the energy used for heating purpose. The mathematical certificates are not provided in attend to the planning but, usually after a prompt note is written, delivered subsequently. General possibilities to optimise the main body of building - that often can save costs - aren’t given anymore.
Architects and planning engineers, who already have realised an apartment house, underestimate the considerable demands on terrace houses, too the adverse proportion of surface to volume of terrace houses means more transmissions losses of energy refer to the dwelling space. To observe the low energy standard of Freiburg in correlation with some town planning founded points of the development-plan, it is necessary to use more heat insulation for external components in addition with waste-air-systems and/or improved window constructions.
The terrace-house groups showed an increase of the provable used energy for heating purpose after sending a revised evidence respectively after a site-date in average from 67,5 kWh/m²a to 70 kWh/m²a.
Altogether we can say, that f. e. terrace-middle-houses with a heat-technical-construction of the thermal building-case corresponding with the actual technology, reach the limit value of 65 kWh/m²a. But if there are in addition some town-planning dependent points f. e. slipped parking, the limit value will be linked with an enormous technical and financial expenditure. Terrace-end-houses turned out that the energy-consumption-characteristic-value, corresponding to above specified heat technical construction, often is above the limit value. Because of that f. e. Hessen - the pioneer in the German Federal - laid down a higher value for family houses.
Sumn avail themselves of the offering of planning support by the city office Rieselfeld, through which already in approach mistakes of calculating the evidence can be avoided and ideas, relating to possibilities to optimise the planning and construction of the main body of the building, can be early taken in.
The city office Rieselfeld will deepen the information-work and will set on earlier to assure that the specific low-energy-house-demand in case of building planning will be taken in consideration as soon as possible. Altogether the development can be seen to be agreeable. By a long way the low-energy-house-standard is an important commercialising argument for the investors.
Controlling the low-energy-house-construction at the building area Rieselfeld shows a clear tendency. Projects handled by a turn-key-building-firm often did better than projects done by architects handling with single firms. Most of the turn-key-building-firms are certificated by DIN EN ISO 9000 and have a respective quality-management. The planning engineers, working in commission of those firms, more ofte
SOURCES: CLEI International Council for Local Environmental Initiatives, 1993: Local Initiatives ICLEI Members In Action 1991-1992, Toronto, Ontario, Canada
| Name | : | City of Freiburg |
| Firstname | : | |
| Telefon | : | +49 / 761 216 3810 |
| Telefax | : | +49 / 761 216 3036 |
| Address | : | Stadt Freiburg |
| Umweltdezernat | ||
| Rathausplatz 2/4 | ||
| 79098 Freiburg | ||
Project was added at 01.06.1995
Project was changed at 01.06.1995