Executive Summary

Europe is facing four interconnected crises: unaffordable housing, unhealthy homes, energy and resource insecurity,
and climate and biodiversity breakdown. Each is considerable in its own right, yet they share a common thread. Europe’s buildings sit at the intersection of all four, which makes the built environment not only part of the problem but also a decisive part of the solution. The EU faces a significant housing gap, with an estimated need for more than 2 million additional dwellings per year to meet the current demand. At the same time, buildings account for 40% of final energy use and 36% of energy-related greenhouse gas emissions in the EU, with 75% of the existing building stock remaining energy inefficient. Poor housing
comes at a cost for the health of the European population, with a third of Europeans being exposed to unhealthy indoor climate conditions.

Europe’s housing challenge is not simply to build more homes, but to ensure access to affordable, adequate and healthy housing that matches people’s needs and circumstances. It is becoming increasingly evident that new construction alone cannot solve the affordable housing crisis, as it is not merely a market mismatch. Moreover, new buildings require substantially more materials and resources than renovating and making better use of existing homes. This poses a fundamental question about how Europe should approach these interconnected challenges and whether the solutions could be found in what has already been built.

Most of the buildings Europe will rely on in 2050 are already standing, with around 85% of today’s building stock expected to remain in use. Yet the current distribution of the existing building stock does not fully match the needs of the population, with large shares of homes being underoccupied or overcrowded, while most of the stock is in desperate need of energy and comfort upgrades. Making better use of Europe’s existing building stock can help address the housing and climate challenges while also strengthening resilience and making Europe more robust and future-ready in the face of energy, resource and geopolitical turmoil.

This green paper is an invitation to discuss how Europe can better use its existing buildings. It presents a technical and theoretical analysis of the potential of renovation, including the reuse of vacant homes and the conversion of unused
buildings into housing, which unlock more floor space without new construction. The paper proposes a spectrum of measures to better use the European building stock and investigates their impact on reducing embodied and operational emissions, as well as resource consumption.

The result of the analysis is the Impact Framework, a prioritisation hierarchy showing how buildings can achieve substantial reductions in carbon emissions and resource use.

• Renovate first. Work with what is already standing. Resize, reclaim, repurpose, refine and reshape, before reaching for heavier interventions. These strategies unlock capacity, cut energy demand, improve living conditions, and reduce emissions without the material burden of new construction.
• Then extend. Unlock the attic. Build up. Build out. Use these measures where renovation alone cannot meet demand, and where existing structures can support additional capacity without starting from scratch.
• Build new only as a last resort. When new construction is genuinely needed, it should be compact and designed under sufficiency principles. Conventional construction should be treated as the reference case Europe is deliberately moving away from, not the standard to continue.

Applying the proposed Impact Framework to the eligible European building stock reveals that existing buildings hold the potential to meet housing needs while reducing emissions, resource use, energy dependency, and public health costs at the same time. Between 50 and 107 million homes could be created, housing an additional 120–250 million people in areas where supply is limited and demand is highest.

Applying the proposed better-use measures could provide enough housing capacity to meet the demand, even in the most constrained markets, reducing or avoiding the need for new construction. Just as importantly, they can expand the range of housing options available, helping to better match existing homes with people’s housing needs.

A better use of the existing building stock avoids between 3.9 and 19 billion tonnes of CO₂ over the next fifty years. The better-use measures could cut the construction industry’s footprint by up to 32% over that period. At the European level, the savings equals 2 to 11% of all emissions across every sector of the EU economy. The upper end equals the emissions of France. Or Spain. Or every car on every European road combined. Assuming deep energy renovations are triggered in all buildings undergoing these measures, additional emissions of 4 to 5.5 btCO₂eq can be avoided.

Moreover, between 5.8 and 13 Gt of material use can be avoided through better use of the existing building stock. Reducing material consumption will avoid unnecessary pressure on the ecosystems and prevent further biodiversity loss.

Contents

• 00 Executive summary
• 01 Europe’s housing future at a crossroads
• 02 The buildings are already here
• 03 A spectrum of measures
• 04 Methodological approach for quantifying the potential
• 05 Not all housing solutions are equal
• 06 A hierarchy for action
• 07 Estimating the potential of using buildings better at the European scale
• 08 Key takeaways & A call for discussion

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