A Review of Non-Residential Building Renovation and Improvement of Energy Efficiency: Office Buildings in Finland, Sweden, Norway, Denmark, and Germany

Existing buildings are a source of great potential for energy efficiency through renovation. In this study, the national energy requirements equivalent for the major renovation of existing non-residential buildings using the example of office buildings in five European case countries are drawn out and discussed. The non-residential building sector has been found to be complex and heterogenous with much less available data than for the residential sector, but having greater average specific energy consumption per floor area. The existing non-residential building stock in the studied countries has been divided into varying amounts of groups and sub-groups. The energy requirements have been shifting from the increasing requirements for the U-values of the building envelope (before the 2000s) towards calculated energy demand for buildings as a whole (currently). The requirements for buildings in the near future will be carbon emission based. The energy efficiency of N-RBs in all of the studied case countries have been steadily improved during different decades of construction. Relatively older office stock combined with the relatively late introduction of national energy requirements was found to have a significantly larger potential for energy savings. Different terms and contents in national requirements were used to describe the principles of “major renovation” as from EPBD.