Each of the 11 technical chapters (3 through 13) begins with an overview followed by each subsystem. For the building envelope, subsections include fenestration, insulation, infiltration, etc. For HVAC, the subsections include heating equipment, cooling equipment, and ducts. Mandatory measures and prescriptive requirements are described in each subsection or component. The prescriptive requirements establish the stringency of the Energy Standards because they are the basis of the energy budget when the performance compliance method is used.