Project North is a low energy retrofit with a mansard roof and side infill extension. It challenges the traditional ground floor organisation of the english terraced house moving the kitchen to the front. Spaces now take on several functions and visibility on ground floor is created from the front into the garden. A previously dark and cold Victorian house was transformed into house that is now bathed in daylight. We designed a mechanical ventilation system with heat recovery which delivers fresh air and helps to reduce heat loss. The EPC was improved from a D to a B and running costs have shrunken. Its mansard and side infill extensions are designed to the german passive house standard, the highest fabric performance standard in construction.