When external conditions are at their most extreme, a 100m Passive House will only need a 1KW heater to maintain an internal temperature of 20 °C. Over the period of a year the same Passive House will use less than 1500KWh of heating energy. That's a maximum of 195 in annual heating costs. Poulter Architects contributed a case study to this book which demonstrates how we use Revit to produce project information at every project stage. In the foreword, David Philip who is head of the UK BIM Task Group states.