The calculation method used by a Domestic Energy Assessor is known as Reduced Data SAP (RdSAP). SAP stands for Standard Assessment Procedure. SAP was created by BRE and has been in use for many years as a tool to measure the energy efficiency of buildings.

RdSAP. As its name suggests, uses less information than full SAP to make the same energy calculation. This is achieved by making assumptions based on the age of a building and other factors. Years of research have established that as building standards and regulations have changed over time certain characteristics of a building can be inferred from its age and building style. Statistically a pre-war brick building will have walls with a high U-value. The size of windows started as quite small, became larger in the 60’s and then reduced again as society became more energy conscious.

Energy Assessors may be qualified to several different levels: Domestic Energy Assessor (DEA), On Construction Assessor, Commercial Level-3, Commercial level-4, Commercial level-5. Energy assessors are trained by Accreditation Agencies. The DEA course typically costs £1,200 plus expenses and takes several months to complete. The course covers not only building knowledge and survey techniques, but also consideration of customer care and business ethics. As with most occupations, it is important to keep up to date, There is a requirement to participate in several hours of Continuous Professional Development (CPD) each year.