U Values England & Wales
The UK government has announced amendments to Approved Document L: Conservation of Fuel and Power, and the implementation of the European Unions’ Energy Performance of Building Directive (EPBD). The revised Part L 2006 regulations came into effect on the 6th April 2006.
To satisfy the requirements of the EPBD, new improved energy performance standards of 20% – 28% have been set for all new buildings, based on the ‘whole building’ Target CO2 Emission Rate (TER).
Methods of compliance
A key requirement is that an overall energy performance target must be set for each new building. This means the demise of the three alternative methods of compliance currently allowed in ADL1 (New dwellings) and ADL2 (New buildings – other than dwellings).
Note: It should be noted that dwellings refer to self contained units. Buildings which contain ‘rooms for residential purposes’ i.e. nursing homes, student accommodation and similar are not regarded as dwellings and so ADL2A (SBEM methodology) applies.
Elemental U values
For new buildings (L1A and L2A) the Elemental U value route will no longer form a stand alone means of meeting compliance, other than providing set minimum acceptable performance standards for the building envelope. The Elemental U value route may, however, be used to show compliance for extensions and refurbishment work to existing buildings.
Notional Dwelling
The ‘notional dwelling’ is the benchmark against which the 20% energy saving is assessed. (28% for non-dwellings). The reference values to be used in the notional dwelling are set out in Appendix R1 of SAP 2005.
