The energy efficiency of the two modern Alterra buildings is no better than that of the fifty-year-old Dreijenborch building.
A group of students doing the MSc course in Urban Environmental Management was given an assignment by Dr Okke Braadbaart to evaluate the environmental performance of the three buildings. Everyone was surprised that such an old building, constructed in the time when energy performance was not even an issue, should be just as energy efficient as the new buildings. Braadbaart thinks he knows why: “If the construction of a building is simple, using only a few different materials, energy losses tend to be low. If you use lots of different building materials in a complex structure you get air currents, which cause heat loss. Materials expanding and contracting also leads to heat loss through cracks.”