Renovation / energy efficient upgrades

Very substantial energy savings are possible with refurbishments of existing buildings. The main focus is on the following aspects:

•Improved thermal insulation (based on the principle “if it has to be done, then properly”)

•Minimisation of thermal bridges

•Improved airtightness

•Use of excellent quality windows

•Ventilation with efficient heat recovery

•Efficient heat generation

•Use of renewable energy sources


These are the same measures that have also proved successful in new constructions. A large number of examples of retrofits demonstrating the use of highly efficient technology in existing buildings have been carried out. Energy savings between 75% and 90% have been achieved; however, due to the thermal bridges that still remain after refurbishment of existing buildings, achieving the Passive House standard is not always a realistic goal. The Passive House Institute has therefore developed the "EnerPHit – certified refurbishment using Passive House components" certification procedure for such buildings. The Passive House Institute provides consultation services for refurbishment projects and carries out measurements in refurbished buildings.