Show Filters
Part L Energy Conservation

Appendix C - Reference values for calculation of MPEPC and MPCPC




This Appendix provides a set of reference values for the parameters of a DEAP calculation, which are used in connection with establishing an EPC and CPC for a dwelling for the purposes of demonstrating compliance with Regulation L3(a) for new dwellings. Table C1 is used to define a notional reference dwelling of the same size, i.e. same floor area and volume, and with the same area of opaque fabric elements, i.e. wall, roof and floor, as a dwelling being assessed. The total external window, rooflight and door area is taken to be 25% of the dwelling floor area.

Table C1 – Reference Values


The primary energy consumption and CO~2~ emissions per unit floor area calculated for this reference dwelling are used to calculate the primary energy performance coefficient (EPC) and carbon performance coefficient (CPC) respectively for a dwelling being assessed. These, in turn are compared to the MPEPC and MPCPC in order to demonstrate compliance for the dwelling being assessed. An example of a typical dwelling specification which complies with the MPEPC and MPCPC is given in Appendix E.


The main heating system for space and water heating in the reference dwelling is assumed to be natural gas, while the secondary system is assumed to be an open fire. Some 10% of space heating is assumed to be provided by the secondary heating method.