Harry Paticas is the founder and managing director of RAFT - an architect, passivhaus designer and recognised expert in the field of building retrofit. Harry has lectured widely on the subject of building retrofit and is a technical expert for the AECB, STBA and Passivhaus Trust. His own home is an innovative low carbon retrofit and is the UK's first step-by-step Passivhaus Enerphit project. Bob Prewett has been working on deep low energy retrofits for over 15 years, with numerous projects being regularly referred to as exemplars. He has lectured and written widely on the subject and coined the term retrofit coordinator which has grown into a level 5 qualification and underpins the PAS 2033 standard.