Do Historic Buildings Have Poor Energy Performance, and Will Energy Optimization Compromise Their Historic Values? A Study of Danish Apartment Buildings

Historic buildings are often assumed to have poor energy performance, and energy optimization of the buildings is perceived as threatening their cultural values. This study tests these assumptions. First, it examines the energy performance of Danish historic apartment buildings (buildings constructed before 1950 with a high preservation value, according to the national SAVE system (Survey of Architectural Values in the Built Environment)). Second, it assesses the extent to which the energy improvements in the historic buildings conflict with their historic value. An analysis of energy performance certificates (EPC) in 13,000 Danish historic apartment buildings reveals that they perform no differently than apartment buildings with a low preservation value, with 46% of historic apartment buildings achieving an EPC rating of “C”. Nevertheless, significant potential for further energy improvements is identified. Expert interviews and three case studies indicate that typical interventions for enhancing buildings’ energy performance rarely interfere with its historic values. This is partly due to structural conditions where shoulder-by-shoulder location, high building compactness, and supply with district heating gives a beneficial foundation for a high energy performance. Potential conflicts between energy improvements and historic values exist but are often resolved through dialogue between local authorities and owners about the interventions.