2.1 This Approved Document, which takes effect on 1 October 2010, deals with the energy efficiency requirements in the Building Regulations. Regulation 2(1) of the Building Regulations defines the energy efficiency
requirements as the requirements of regulations 23, 25A, 25B, 26, 28, 29 and 40 and Part L of Schedule 1. The energy efficiency requirements relevant to this Approved Document, which deals with existing dwellings,
are those in regulations 23, 28, 29 and 40 of, and Part L of Schedule 1 to, those Regulations and are set out below.