The document discusses sustainable building and moving towards truly zero carbon buildings. It argues that current standards and practices in the UK construction industry are insufficient and green claims are often misleading. True sustainability requires an holistic approach that prioritizes building fabric improvements, natural materials, passive design, and mechanical systems only as needed. The key areas to focus on are space heating, domestic hot water, ventilation, and moisture management through breathable walls. Simpler construction methods are also advocated for along with changes across the entire industry and supply chain.