Energy efficiency: behavioural effects of occupants and the role of refurbishment for European office buildings

Abstract Energy consumption in office buildings is determined partly by fixed building characteristics, but also by the behaviour of occupants. Within the European Union, office buildings have become subject to more stringent energy efficiency regulation for new construction or extensive refurbishment, with the aim to reduce energy consumption and carbon emissions. The study determines the influence of physical building characteristics and occupant behaviour on energy consumption, and in particular, the role of refurbishment in different intensities on energy consumption is investigated. The data-set of the Green Rating Alliance is tested to provide evidence, by applying multiple regression models for energy consumption. The results highlight considerably increased energy consumption of single-tenant compared to multi-tenant office buildings. Very large office buildings consume significantly more energy per square metre that their smaller peers. A building’s modelled water consumption turns out to be a good indicator for the actual energy consumption, emphasising the importance of assessing further sustainability measures. Overall, buildings of higher age turn out to be of lower energy consumption, pointing to additional appliances and equipment in more recent buildings, to provide better services and more comfort. In general, extensive refurbishment measures account for significant higher energy use, since the overall quality of the buildings is improved with additional appliances and equipment. Testing for the interaction effect between building age and refurbishment, the results demonstrate significantly lower additional energy consumption for buildings with more recent extensive refurbishment, compared to those with refurbishment several years ago. However, the results need to be considered with precaution against deriving firm conclusions due to the small sample size and some drawbacks in the applied data-set.