Fraunhofer Institute for Energy Economics and Energy System Technology
WaeWeWo – Socially equitable heat transition in existing housing stock
The WaeWeWo joint project addresses the conflict of objectives between climate compatibility, economic efficiency, and social compatibility in Germany's rental housing stock. The starting point is the high final energy demand of the building sector, coupled with a large renovation backlog and the particular challenge in the rental market: landlords decide on energy-efficient renovations and bear the investment risks, while tenants bear the ongoing energy costs and possible rent increases. Regulatory frameworks such as modernization surcharges and CO2 cost tier models change the distribution effects but do not completely resolve the landlord-tenant dilemma; low-income and vulnerable households that lack opportunities to participate are particularly affected.
Project Objective and Method
The objective of the project is to use the real-life example of the Wiederaufbau eG building cooperative to develop practical compromises that combine climate compatibility, warm rent neutrality or mitigation, and economic efficiency. To this end, the perspectives of housing companies, tenants, and associations are being surveyed and brought together through optimization. A decision workshop (Decision Theater) promotes participation, transparency, and mutual understanding; the aim is to develop a viable roadmap that is accepted by all stakeholders.
Representative scenarios covering around 80% of the rental housing stock are defined for transferability. Based on this, optimized combinations of renovation schedules, financing, and allocation mechanisms are calculated and made available as a publicly accessible dashboard (open data) to make investment decisions and distribution effects transparent. The project is aimed at policymakers and local authorities, housing companies and cooperatives, energy consultants, and tenants. It aims to empower stakeholders, provide faster investment clarity, accelerate renovations, provide targeted support to vulnerable households, and identify transferable methods for a socially just, climate-compatible housing stock.
