An EPC can only be produced by a Domestic Energy Assessor (DEA) or a Home Inspector (HI) who is a member of an approved Government Accreditation scheme. The energy assessor will visit the property to determine the energy related features. These are then entered into a computer program which has a calculation model developed by the government and is known as Reduced Data Standard Assessment Procedure (RDSAP).
RDSAP is a cost-based rating system which uses pre-determined assumptions. It does not look at the appliances, but rather the performance of the building itself in areas such as heating and lighting. In other words, it provides an energy efficiency rating for the property itself rather than an occupancy rating.
When collecting the RDSAP data the energy assessor will need to determine the following:
- Property type
- Age of property
- Type of construction
- Property dimensions
- Room and water heating systems
- Insulation levels
- Windows and glazing types
- Types of lighting
This information will be entered into the calculation software and an EPC will be produced.