LooKIT-Interview: „We must eventually start measuring CO2 emissions instead of insulation thickness only“
Despite high energy-efficiency standards, buildings account for around 40% of the CO2 emissions in Germany. This is why a number of scientists have published a manifesto with the aim of initiating a change of policy in the building and refurbishment sectors. “We have been relying on the same policy for decades – without achieving significant CO2 savings,” says Dirk E. Hebel, Professor of Sustainable Construction at KIT’s Department of Architecture and co-author of the manifesto. Since the oil crisis in the 1970s, the focus lies on the efficient use of energy. “To meet the housing subsidy standards, buildings must be insulated effectively. While the HVAC technology is becoming increasingly com-plex, energy consumption stagnates and emissions remain on a high level. We need to give up focusing on efficiency and tackle the emissions side directly,” says Hebel.
The initiative proposes that the amount of CO2 emissions over a building’s entire life cycle be considered. This includes the production of the materials, the construction of the building, and its operation. “Only if a clear CO2 target value – which must be at net zero by 2045 – is met, a building permit should be granted,” says Hebel. Take Denmark as a model: The Danish authorities specify target values in kilograms of CO2 equivalent per square meter of floor space and lower those targets regularly. The current value is 7.1 kilograms. Those who undershoot the target value are entitled to construct, reconstruct, refurbish, or extend a building. No matter whether this is achieved through preservation of building stock, use of recycled materials or by operating with renewable energy – it is the result that counts. – Extract of Interview by Christoph Karcher. LooKIT 0225, 2025.
