Purpose of the project
The Mundsburg Office Tower was erected between 1969 and 1971 and is situated in Hamburg Barmbek. As a mixed-use building it houses offices, residences and a shopping centre. With its height of approximately 100 m the office tower is one of Hamburg’s tallest and best-known office buildings in the city. After 40 years of existence without any substantial refurbishment the building contained all the typical problems from this period and was entirely redeveloped by alstria between 2010 and 2012. Today the office tower consists of approximately 9,500 sqm of state-of-the-art office space on 20 floors.
Alstria’s approach to the real estate market is based on the idea that there is enough existing space in order to house all needed activities in most of the advance economies. Therefore there is no need for new off ground development and use of natural resources for theses. Our “development business” is therefore focussing on redeveloping and repositioning existing buildings, which allows us to reuse most of the existing structure of the asset while substantially improving it overall performance.
The Mundsburg Office Tower was repositioned in a way that reuses most of its grey energy (embodied carbon in the structural body) and by solving all mayor operational problems.
The redevelopment of the building was necessary given that after 40 years of use, the office areas did not meet today’s demands for a modern and economic working space. The energy efficiency and sustainability of the building were especially suboptimal. The main aim was to create flexible office spaces with state-of-the- art building services. The interior space was completely redesigned and the office structure optimised.
To enhance the overall energy efficiency of the building, the façade needed to be completely rebuilt and improved for the winter and summer periods. It was essential that the character of the façade was not changed as the tower is listed as a monument building. After the development, the Mundsburg Office Tower is again fully integrated into its surroundings.
An essential element of the technical modernisation was the complete replacement of all building services. All components were in a very poor condition and therefore very inefficient. Due to an upgraded façade the new building services are very efficient and energy-saving. The office users have a much higher comfort level with these systems. The existing foyer needed a redesign as it was very small and non-representative. Now the lobby is generous, bright, inviting and suitable for wheelchair use.
After the completion of the redevelopment the building is occupied since 2013. An energy saving potential of 78% was calculated in the design stage. It was important for alstria to check that this theoretical calculation was reflected in actual results.
The actual consumption for heating in 2013 confirms the saving potentials of the design calculation. Approximately 80% of the heating energy could be saved as predicted. This is equivalent to approximately 2,500,000 kWh (2.5 GWh) per year and corresponds to the energy consumption of approximately 170 typical households. Thanks to the redevelopment of the office tower the CO2-emission can be reduced by 1,103 t per year.
After the modernisation, the electricity consumption in the common areas was reduced by more than half. This positive outcome is due to the usage of modern building services like new mechanical ventilation, new lifts and LED-lighting. In 2013 approximately 284,000 kWh of electricity was saved. This relates to the electricity consumption of approximately 95 typical households. The CO2-emission was reduced by 125 t/ year.
In total more than 1,200 tCO2 per year can be saved with only one redeveloped building. This is equivalent to the carbon absorption of an area of European forest in the size of approximately 168 soccer fields. This was achieved by creating state-of-the-art offices for nearly the same gross rent as prior to the refurbishment.
The Mundsburg Office Tower was one of the first buildings in Germany to achieve a DGNB Green Building Certification in Silver for refurbishment of existing building in 2013.
“The most sustainable building is the one you did not have to build. In most of the advanced economies, we should stop building ground-up development, and start retrofitting existing buildings. There is a substantial natural resources and grey energies embodied in our cities that can be easily given an new life.”
-Olivier Elamine, CEO of alstria office REIT-AG