The ecological pay-back challenge of energetic retrofits – What's a smart low carbon investment approach

Recent studies have shown an increase of Embodied Carbon of buildings while operational emissions were reduced in many countries. Since renovations are crucial to tackle climate crisis, this paper aims to investigate to what extent embodied carbon of energetic retrofits is beneficial from an ecological perspective. In particular, this paper researches the question of how long the carbon payback period is for the asset classes and on which ones the focus should initially be in the upcoming modernisations. Starting off with a literature review on embodied carbon in building materials and construction, a set of case studies is then analyzed in terms of avoided emissions and embodied carbon emissions that come along with the retrofit. Typical renovation packages and scopes are compared with each other by calculating the environmental impact as well as their economical payback period. Subsequently, the energy consumption before and after retrofit is considered and the extension of the life cycle by the measure is evaluated. As a result, benchmarks will be established for different energetic retrofit measures in different regions. This paper helps to prioritize retrofit measures from an ecological point of view and at the same time is to the best of the authors' knowledge a first-time framework for the comparison between emission savings and initial carbon emitted during the retrofit.