The STANDARD ASSESSMENT PROCEDURE FOR THE ENERGY RATING OF DWELLINGS (SAP) was developed by the BRE and was first published 1992. It has since been adopted by the UK government as the recommended methodology for measuring the energy rating of self-contained dwellings and individual flats and is used as the basis for checking that new dwellings in England and Wales comply with PART L of the building regulations. SAP calculations are used to produce EPC certificates for new dwellings, while a more simplified version called RDSAP (Reduced Data SAP) is used to produce EPC certificates for existing dwellings. SAP calculates the typical annual energy costs for space heating, water heating, lighting, and the CO2 emissions. SAP ratings are expressed on a scale of 1 to 100+, with higher rating indicating lower energy consumption and lower costs, and a rating exceeding 100 would indicate a dwelling that is a net exporter of energy. Since the first version was published in 1992, there have been numerous updates with the latest version released in 2012. The next update, referred to as SAP 10, is under development and is likely to come into force in conjunction with the launch of the FUTURE HOMES STANDARD in 2025.