Photo credit: EU-GUGLE

Built in the 1970s in Aachen, Germany, these four apartment buildings were energy renovated as part of a district wide regeneration programme.  Its use of innovative heat pump technology linked to a highly energy efficient envelope led to the achievement of 54% energy savings

Some of the buildings in the Aachen regeneration scheme had to be renovated while the inhabitants stayed in residence.  Many have been living in their apartments for a very long time and they have relatively low rents. Under the German law, landlords can increase the rental fee by a certain amount to recover costs for energy saving measures over time.  This is very difficult in the houses with low income residents.


Apartments in other buildings will be renovated while the tenants are not in residence, so the possibilities to adapt the rental fee to the new standard are easier.  A significant aspect of this project was the work done by the City of Aachen in educating and informing residents on the benefits of energy renovation and how renovating their buildings would bring benefits in the long term.  Vouchers were given to residents to avail of a consultation from one of the City of Aachen’s energy specialists.


Principal Characteristics of the Renovation Works:

Ownership type: Public
Year of construction: Circa 1972
Renovation completed: 2016
Floor area after works: 10,100m²
Structure: Loadbearing reinforced concrete frame with masonry infill that was over clad with an ETICS system combined with roof and basement insulation.  All external balconies and windows and doors were replaced
Heating and energy: Heat pumps were installed taking heat from a nearby canal and from underground sewers.  New heat recovery ventilation was also installed, and all electrical installations renewed
Energy performance: Energy savings after works reached 54%
Cost of works: €7.7m (€760 per m²)
Architect: Gewoge AG
Technical consultants: Ing.-Büro ECO.S Stodtmeister

Post on the EU-GUGLE project from the City of Aachen’s website:

EU-GUGLE Blog post on Aachen: