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Hamburg architect interviewed on NDR Market TV about architectural renovation of buildings and “grey energy”

Architect Justus Asselmeyer advocates for more sustainability in buildings, rather than building new ones

TV interview on NDR Market about the architectural renovation of buildings and Hamburg (pts019/14.02.2023/10:30) – Hamburg architect Justus Asselmeyer was invited to a TV interview on NDR Market due to a press comment on the architectural renovation of buildings and “grey energy”, to discuss the need for sustainable building. Asselmeyer and his architecture firm specialize in “identity architecture” and advocate for the longest possible use of buildings, rather than constantly building new ones. “Grey energy” in architecture refers to the energy and resource consumption required to construct a building, including energy for producing building materials, manufacturing, processing and installing building components, transporting people, machinery, building components and materials to the construction site, and ultimately disposal. This is a huge sector in Germany. “Those who act more carefully and sustainably here can save huge amounts of energy and resources,” emphasizes architect Asselmeyer in the TV report, while also showing examples of renovation for modern and sustainable building.

Interesting environmental building facts that are surprising:

  • The living space per person has increased by 20% in the last 20 years.
    On average, the living space per person increases by one square meter every five years. In 2020, the federal average is around 45 m2 per person, compared to 36 square meters per person in 1995 – a fifth less!
  • 11% of global CO2 emissions come from the production of building materials (30% of all emissions for the construction of a building and its life cycle).
  • In a new building (e.g., KfW55), grey energy accounts for about 50% of energy consumption over the life cycle (calculated over 50 years), compared to conventional buildings, which account for about 30%.
  • As the Climate Protection Plan aims to transition to renewable energy by 2050, the share of grey emissions over the entire life cycle is a staggering 80%.

One thing all experts agree on: 100-year-old buildings have a better overall energy balance than newly built passive houses. The use of regionally sourced materials and resource-efficient construction can minimize the “grey energy” used in a building, but it cannot be prevented. Ultimately, it is not just the construction industry or decision-makers; it is also the people themselves who, as users and occupants, decide how to manage energy and emissions.


Link to the press article:
The contribution can be seen in the NDR Mediathek:,markt16330.html
The contribution watch on youtube:
Info on the architecture firm and the concept of identity architecture at:


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