Esys recommends: Renovate the worst buildings first

20.03.2025

Source: E & M powernews

Even in 2024, the building sector has hardly been able to reduce its greenhouse gas emissions. Two new publications from the Academies' Initiative "Energy Systems of the Future" (Esys) recommend solutions.

According to experts from the Esys academy initiative, renovating the worst-performing buildings (WPBs) in terms of energy efficiency is the most effective lever for reducing greenhouse gas emissions in the heating sector. At the same time, social sustainability should be taken into account in order to mitigate financial hardship, the scientists recommend. In addition, the level of knowledge about buildings in Germany must improve in order to implement targeted political measures.

Without the energy transition in the building sector, climate neutrality cannot be achieved by 2045. Buildings account for around 40 percent of greenhouse gas emissions in Germany and the renovation rate has only been around 1 percent for years. Two recent publications from "Energy Systems of the Future" (Esys) recommend measures to accelerate the heating transition.

Renovate the worst buildings first

Buildings with the worst current energy standards are characterized by above-average greenhouse gas emissions. Targeted upgrading of these buildings to low-temperature capability and converting them to a climate-neutral heat supply will therefore reduce emissions particularly quickly. "As an incentive for the refurbishment of WPBs, a mix of instruments will probably be necessary, which, in addition to the CO2 price, also relies on more focused and increased subsidies," explained Andreas Wagner, head of the study.

Regulatory requirements could also make a contribution in the final instance. "However, it will be important to implement sensible accompanying measures that provide information, advice and social cushioning," Wagner also warned. In view of the weak data situation in the German building sector, knowledge of WPBs and their occupants is limited and information on other building segments is only approximate, the researchers criticize.

The poor data situation makes it difficult for legislators to take targeted political measures and assess their impact. "In addition to quality, the provision of data in Germany must therefore also improve," according to the analysis. This could be remedied, among other things, by more and higher-quality energy performance certificates, the information from which is entered into a central and publicly accessible database.

Consider social sustainability

"To ensure that the heating transition is not only ecologically but also socially sustainable, vulnerable groups must be given greater protection," emphasized study director Melanie Jaeger-Erben. They are often faced with a dilemma between housing and renovation costs. "As refurbishment is not financially affordable for them, housing costs also rise with the constant increase in the price of CO2," she described. This dilemma needs to be overcome and people need to be involved in the heating transition.

"To achieve this, it is also important to give people the opportunity to reduce their energy and land consumption," said Jaeger-Erben. Proactive and well thought-out communication as well as local and target group-oriented contact points could support social participation, she suggests.
Esys is a joint initiative of Acatech, Leopoldina and Akademienunion. The working group was led by Melanie Jaeger-Erben (Brandenburg University of Technology Cottbus-Senftenberg) and Andreas Wagner (Karlsruhe Institute of Technology).

The Institute for Ecological Economy Research (IÖW) presented its study "Socio-technical analysis of WPD in Germany". This looks in detail at who is particularly affected by the heating transition and changing energy/housing costs and how these groups can be supported. The authors emphasize that the climate protection targets cannot be achieved without adapting land and energy consumption.

The impulse papers are available for download as recommendations for action and analysis on the Esys website.

Author: Susanne Harmsen