Section 2 Existing dwellings
L1 A building shall be designed and constructed so as to ensure that the energy performance of the building is such as to limit the amount of energy required for the operation of the building and the amount of carbon dioxide
(CO2) emissions associated with this energy use insofar as is reasonably practicable.
L2 For existing dwellings, the requirements of L1 shall be met by: -
(a) limiting heat loss and, where appropriate, maximising heat gain through the fabric of the building;
(b) controlling, as appropriate, the output of the space heating and hot water systems;
(c) limiting the heat loss from pipes, ducts and vessels used for the transport or storage of heated water or air;
(d) providing that all oil and gas fired boilers installed as replacements in existing dwellings shall meet a minimum seasonal efficiency of 90% where practicable.