Challenge

To meet ambitious climate targets, such as the 2035 emission goals, cities must rapidly decarbonise their building stocks. However, municipalities face multiple, overlapping challenges: high debt burdens, slow and fragmented renovation processes, material and labour shortages, and the sheer scale and complexity of their building portfolios. In Nuremberg alone, the city manages over 1,900 buildings. Traditional retrofitting approaches tend to prioritise large buildings, yet most urban building stock consists of small to medium-sized properties with moderate energy performance. Current planning methods are often too resource-intensive or inflexible to handle such diverse and distributed building types. Without a smarter, scalable approach to energy renovation, cities risk falling short of their climate commitments.

Solutions

ZEROit responds with a suite of three integrated solutions that aim to accelerate the renovation process while maximising emissions reductions:

1. The Holistic Portfolio Planning Tool (HPP-TOOL) supports strategic decision-making across large and complex municipal building stocks. It helps cities allocate investments efficiently, prioritising buildings and interventions that yield the highest carbon savings under budgetary constraints.

2. The Rapid Zero-Emission Renovation (RAZE-RENOVATION) methodology enables the fast and cost-effective retrofitting of small and medium-sized buildings using existing market-ready technologies. This solution focuses on replacing fossil fuel heating with efficient systems such as heat pumps and prepares buildings for future envelope upgrades without requiring immediate, full-scale renovations.

3. The project also supports stakeholder and citizen engagement, including the deployment of a One-Stop-Shop (OSS) that pilots the HPP-TOOL and facilitates participation, awareness, and uptake of renovation measures.

Results

ZEROit empowers cities, so far- Nürnberg,  to develop realistic, step-by-step decarbonisation pathways for their entire building stock. By providing practical tools and scalable methods, it helps municipalities overcome technical and financial barriers to renovation. The project improves planning capacity, accelerates implementation, and increases public trust and participation through citizen-oriented engagement. Ultimately, it contributes to achieving EU climate goals by transforming renovation from a slow, isolated process into a fast, coordinated and cost-effective strategy.