FAQ Concerning the Energy Performance Certificate

How is an EPC prepared
An EPC is prepared following a detailed survey of a building by an energy assessor. The objective is to determine how energy is used in the building, in terms of its heating, lighting and control mechanisms. In conjunction with this there is also a determination of how energy escapes from the building in terms of its construction and insulation properties. The survey therefore captures data relating to heating, cooling and lighting inputs, and the detailed dimensions and structures of the building.
What is "SBEM"
The 'Simplified Building Energy Model' is the computer software used to model the results of the survey. The survey data on the building's "geometry" and services are entered into the model and a calculation is performed. The result is the "Asset Rating" of the building.
"Asset Rating"
From the survey data, the computer model calculates a CO2 emissions value for the surveyed building. From its database it also calculates a CO2 emission value for a ‘notional’ building of the same ‘geometry’. The ‘notional building’ fulfils the basic requirements of current building regulations, and has a set regime of heating, cooling and lighting which is related to the use of the real building. The Asset Rating is a comparison of the CO2 values of the ‘real’ and ‘notional’ buildings. A low number indicates a favourable comparison with current building regulations and a good energy performance. A higher number means the ‘actual’ building is poorer than current standards. As well as the rating for the building, each certificate also gives the benchmark scores for a ‘newly built’ and ‘typical’ building of the same type.
How should and Asset Rating be used
Asset Ratings should be used purely for comparison or 'ranking' between similar properties. It would be wrong to conclude that heating bills would be halved between properties with ratings of 50 and 100. However, such a large difference in rating would be significant in terms of fuel cost.
What else is on the EPC.
The EPC gives the details of the building, the date of its survey, and the details of the surveyor and his/her accreditation. The modelling software also produces recommendations for the improvement of energy performance, based on the data inputs and its processing of them. The recommendations are part of the statutory requirement of the EPC, but there is presently no legal obligation to act upon them. Next