This book tells how to insulate your house fully, not just the loft, and together with such things as solar panels get it close to net zero. Adjacent owner-occupiers, most of the street, form a club. Construction professionals are appointed to prepare a scheme and detail it. Surveys and assessments are carried out by scanning externally and internally as well as in traditional ways. Insurers are part of the scheme, covering risks and providing warranties. A builder wins the job and their costs are met by a mortgage from a retrofit building society. The cost of energy saved pays the mortgage. Cracking and other deficiencies and previous ill-advised alterations must first be rectified. The builder then fits external wall insulation in the upper parts of the house, and internal wall insulation at ground storey. Owners remain resident, surrendering rooms by the working day for the latter. This happens along the street. Other necessary things are done. It is shocking, almost the appearance of whole streets change for ever. Serious unanticipated building defects or illness mean the house is given over to the builder for a time, residents moving to a hotel. Kids are then taxied to school. Insurrers cover costs related to such delays. There will be universities of retrofit. Finally, an Enhanced Retrofit Passport certifies the house so 22nd century owners are reassured.