The City of Aachen has 248.000 inhabitants and is situated at the western border of Germany to Belgium and the Netherlands. It is a very important place for science and education with more than 50.000 students in total. The district Aachen-North is a heterogenous area with a mixture of recent and ancient industrial and residential buildings. Due to the development of the last 80 years there are many historical buildings for housing, a lot are listed buildings. Therefore urban planning focuses on revitalizing and improving the attractiveness of the district.
The district Aachen Nord (300 ha, 15500 inhabitants) is part of a multi-year urban development program “social city”. In the model site of the EU-GUGLE pilot about 1.500 residents are directly involved in the buildings.
The Building Stock
The buildings are mainly of 4 different types: historical settlements from the 20s and 30s and multistory buildings from the 70s. The constructural conditions of the buildings and the status of energy supply have to be improved in the coming years. In the urban development program ”social city”, recently implemented, Energy is one aspect besides green places, housing, living quality, leisure, places for culture, social institutions, integration of industry and road space. Special energy saving targets and measures are only foreseen for the buildings within EU-GUGLE.
The Pilot district in figures
- 41 688 m² to be renovated
- 1500 inhabitants in the renovated buildings
- 391 dwellings to be renovated
Integrated solutions in Aachen
- Insulation measures on facades, roofs, cellar ceiling, windows
- heat-recovery from ventilation
- heat recovering from the sewage and heat pumps integrated in a low-ex heat network
- district heating
- technical control systems for heat, electricity and lighting
- solar energy and efficient gas boilers
- presence detectors for lighting
- smart meter
- Energy efficiency rental fee and other agreements with tenants,
- technical measures (temperature on demand,
- communication measures and advisory activities to reduce energy consumption through consumer behaviour.
The buildings are mainly owned by the City of Aachen (75 %) and 25 % by the public housing company GEWOGE, where the municipality of Aachen is an important shareholder. The GEWOGE is operating the complete housing stock.
Some of the energy supply systems will be realized by a contracting model with the local energy company. The investment in the applications, the operation and the maintanance is in one hand. This provides the opportunity for optimized solutions. The CO2-emissions will also be reduced through green energy supply. Other options will be analysed and tested.
Impact for the area
The expected primary energy savings in the EU-GUGLE pilot district are up to 65%.
The envisaged actions are eligible examples of energy efficient retrofitting and have a great potential for immediate replication, first for the other residential buildings from the municipality and GEWOGE (370 dwellings from a stock of over 7 000 are directly involved), but also for many private houses, especially for listed buildings that have to be renovated in the near future.
Some of the buildings in Aachen have to be refurbished while the inhabitants are staying in the houses. Many have been living there for a very long time and they have relatively low rents. Under the German law, costs for energy saving measures can increase the rental fee by a certain amount and give the owner a payback deadline. This is very difficult in the houses with low income residents. Some other buildings will be refurbished while the tenants are not in the houses, so the possibilities to adapt the rental fee to the new standard are easier. In the project different ways will be checked and their impacts analyzed. The activities are aiming also on the task to reduce energy demand by increasing the information and the transparency of energy use.
The main challenges in the work is to realize ambitious measures on a most cost effective way, so that the rents can remain on a socially responsible level, because most of the residents have only low income or receive social welfare. The realization of energy saving measures in listed buildings is a challenge to finding good integrated solutions of construction and energy supply.
The local energy strategy is described in the “Masterplan 2030” and the sustainable energy action plan (part of covenant of mayors and European energy award). Many stakeholders were involved and over a time, a very developed process of discussing energy subjects in the city took place. This is a solid base for EU-GUGLE.