The professions involved in building design are being asked to align predicted energy use in buildings with actual energy use.  Many buildings use more energy than predicted.  This paper summarises a study carried out by Max Fordham LLP in a Knowledge Transfer Partnership with the Bartlett (UCL) that, for the first time, quantifies the impact of building user choices on energy use. It also suggests ways of closing the gap to achieve more energy efficient buildings in practice as well as design.