Housing for millions without new buildings? An analysis of the theoretical housing potential of under-occupied dwellings in the European building stock

Abstract The standard response to the shortage of housing across the political spectrum is to build new housing units. From an environmental perspective, there is a need to decarbonise the housing sector as quickly as possible and to reduce land and resource consumption. This contradiction could be resolved by making more efficient use of dwellings that are under-occupied (for example, after children have moved out). In this article, we analyse the theoretical housing potential of under-occupied living space. To this end, we use established occupancy regulations of Swiss cooperatives and municipal housing authorities, where the number of residents must always be at least equal to the number of rooms minus one or minus two. This defines an upper limit for ‘needs-based living’ that has been tested in practice and is comparatively broadly legitimised. Using this threshold, and based on Data from the EU Statistics on Income and Living Conditions, we identify a theoretical housing potential in the EU stock of approximately 152 million rooms. This implies a theoretical space in the building stock for 50 million additional three-room flats, which equates to housing for 100 million people or 23 % of the EU population. Significant potential exists in all types of regions: cities, towns and rural areas. The under-occupancy is lower in countries with a higher share of small and medium sized flats, which indicates a high influence of the infrastructure on the occupancy. A comparison with the occupancy in Swiss housing markets that have minimum occupancy requirements implemented suggests that a large part of the theoretical potential could be realized by shaping infrastructural and market conditions. We conclude that housing politics should focus on the development of affordable and attractive alternatives for older people and smaller households in order to free up dwellings for families and address social and ecological problems in the housing market simultaneously.