Building function, ownership, and space heating: Exploring adaptive reuse pathways in Swedish building stock

• Adaptive reuse patterns were analysed across 147 000 Swedish buildings. • Energy performance declarations serve as a foundational data source. • Adaptive reuse leads to a significant reduction in space heating energy use. • Converted buildings align with the building stock in age, ownership, and area. • Conversions from office to residential functions are the most prevalent trend. Adaptive reuse, the conversion of existing buildings to new functions, offers a sustainable alternative to demolition and new construction by reducing environmental impact, conserving materials, and minimising costs. This study presents the first large-scale, systematic analysis of adaptive reuse in Sweden, using Energy Performance Certificates (EPCs) from 141 778 buildings issued between 2007 and 2023. EPCs provide measured data on building function, conditioned floor area, construction year, and space heating energy use—a dominant contributor to operational emissions in cold-climate regions. The study identifies common conversion pathways and examines how building characteristics and ownership influence reuse patterns. Conversions were most frequent in buildings sized 1 000–5 000 m 2 and constructed between the 1930s and 1970s. Office–to–residential conversions were most common in absolute terms, but normalised data revealed frequent reuse of care facilities and retail spaces. Ownership analysis showed that corporate and public actors are the primary initiators of reuse, while private and cooperative owners are underrepresented. Energy performance analysis revealed that 82 % of converted buildings were associated with reductions in space heating energy use, and 54 % outperformed their non-converted counterparts. The average reduction for converted buildings was 9.6 kWh/m 2 ·year, compared to 9.3 kWh/m 2 ·year for non-converted buildings; office–to–residential conversions achieved mean savings of up to 19 kWh/m 2 ·year. However, sign tests indicated that statistically significant trends were present in only a subset of conversion pairs, suggesting that the direction of energy use change is not uniformly robust. These differences likely reflect a combination of changes in building use intensity and renovation measures introduced during conversion. The findings demonstrate that adaptive reuse is physically feasible, broadly applicable, and, in some cases, associated with measurable energy efficiency gains. Although national in scope, the methodology is transferable to other regions with structured building energy datasets, and the results are relevant for countries with similar climatic conditions and ageing building stocks. This study provides an empirical basis for cautiously integrating adaptive reuse into energy efficiency policy, housing strategy, and long-term decarbonisation planning.