What are SAP & EPCs?
THE STANDARD ASSESSMENT PROCEDURE (SAP)
The Standard Assessment Procedure is the approved methodology for calculating and comparing the energy and environmental performance of a domestic dwelling. This is a government-regulated procedure underpinning its energy efficiency policies and initiatives. In particular, in 1994 SAP was cited in Part L of the Building Regulations for the 'Conservation of Fuel and Power' in new and existing dwellings. Reduced Data SAP (RDSAP) was introduced in 2005 as a lower cost method of assessing the energy performance of existing dwellings. SAP 2012 is the latest revision of the SAP document which came into force for compliance purposes in April 2014, supporting the 2013 Amendment to Part L which is expected to deliver a 6% improvement in new dwelling performance (SI 2010/2214 as amended).
SAP quantifies a dwelling’s performance in terms of energy use per unit floor area, a fuel-cost-based energy efficiency rating (the SAP Rating) and emissions of CO2 (the Environmental Impact Rating). These indicators of performance are based on estimates of annual energy consumption for the provision of space heating, domestic hot water, lighting and ventilation. Other SAP outputs include estimate of appliance energy use, the potential for overheating in summer and the resultant cooling load.
All new builds and some extensions to existing dwellings or conversions require SAP certification upon completion. However, the use of SAP calculations can prove invaluable from the outset. For house designers and house-builders, a predicted energy assessment (PEA) can contribute to the energy efficiency of a building before a single brick has been laid. By taking advantage of a PEA this can determine the use of energy-saving insulation materials, the installation of effective heating and hot water systems, adequate ventilation and the best use of renewable technologies.
THE ENERGY PERFORMANCE CERTIFICATE (EPC)
The Energy Performance of Buildings Directive (2002) required all EU countries to enhance their Building Regulations and to introduce energy certification schemes. Accordingly, in the UK, the SAP energy rating calculation must be documented within an Energy Performance Certificate (under Regulation 29 Building Regulations 2010). The EPC is necessary to satisfy Building Control that the proposed or existing dwelling meets the standards set within Building Regulations with regards to the conservation of fuel and power.
By law, an EPC can only be produced by a suitably qualified and accredited energy expert. An energy performance certificate must be produced every time a new home is constructed, sold or rented. Moreover, building control will only issue a completion certificate for a new build upon satisfaction that a qualifying EPC has been produced.
An accredited On Construction Domestic Energy Assessor (OCDEA) will use the latest approved software to assist in all energy performance aspects of a domestic-new build. A qualified Domestic Energy Assessor (DEA) will be able to undertake all energy rating calculations to provide the necessary SAP certification for extensions, major renovations and conversions to existing premises.
For further information see the Energy Performance of Buildings (England and Wales) Regulations 2012 (SI 2012/3118) at www.legislation.gov.uk and detailed guidance on energy performance certificates at www.planningportal.gov.uk.