A new short study by the German Sustainable Building Council (DGNB) confirms that renovation is significantly more climate-friendly than new construction. The analysis of 19 DGNB-certified renovation projects shows that CO₂ emissions over the entire building lifecycle are much lower for renovations than for new builds. On average, the building-related emissions of a new construction are 2.4 times higher—and cannot be fully offset even with an energy-efficient operation in the long run.
Why renovation is the more climate-friendly alternative
The goal of the study was to bring scientific facts into the debate on demolition versus new construction. Dr. Christine Lemaitre, CEO of DGNB, emphasizes: “We need to move away from the ‘demolition and replacement’ mindset and focus on preserving and climate-friendly renovating our existing buildings.”
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The analyzed projects mainly included office and administrative buildings, along with some hotels and mixed-use buildings. The structures were built between 1951 and 2020 and underwent renovations between 2018 and 2023. In addition to energy consumption, factors such as types of renovations and specific measures were also considered in the study.
Lower CO₂ Impact Through Renovation
One of the key findings: CO₂ emissions from building materials and construction processes (“embodied emissions”) are up to two-thirds lower in renovations compared to new buildings. While a new build generates high emissions during the construction phase, renovations are the more sustainable option—provided they aim to optimize operational energy use towards climate neutrality.
Early Modernization as the Best Strategy
The study also finds that early modernization is the most effective ecological solution. Even if low-emission construction becomes feasible in 10 to 15 years, the emissions generated in the meantime would outweigh the benefits.
Free Download of the DGNB Study
Dr. Anna Braune, Head of Research and Development at DGNB, summarizes: “Our study provides solid evidence that preserving the existing building stock is the best strategy for sustainable and climate-friendly construction.”
The full DGNB short study, “Climate Impact of Renovations: A Life Cycle Analysis,” is available for free download at:
