The building formerly housing the Faculty of Geodesy at Delft University of Technology had to be renovated to accommodate the laboratories and offices of the Netherlands Institute for Metrology and Technology (NMi). Despite, or perhaps even thanks to, the restricted budget and tight planning, the renovation design has maintained a strong sustainable characteristic. In addition to the fact that renovation is the ultimate form of re-use, maximum use has been made from already existing materials. Thus the existing fašade, including framework, was not demolished but was improved to a better performing fašade which enabled a more comfortable indoor environment. The glass casing around the building creates a cavity that is ventilated with a combination of natural draught and the venturi effect. This helps to keep the heat out of the buildingin the summer and prevents heat loss in the winter and thus leads to considerably improved energy performance.