RdSAP Conventions v9.0

On 1st October 2016 RdSAP conventions v9.0 come into force. All EPCs carried out after 1st October 2016 must follow these conventions and all audits will be carried out against these new conventions.

Most of the convention changes are amendments to existing conventions, but there are also some new ones. 

The new conventions alongside the DCLG information pertaining to the new conventions are available to view on the NES Knowledgebase

Some of the key changes:

Convention 3.04: Loft spaces where the insulation is obscured by stored items are now treated in the same way as boarded lofts.

Convention 3.07: In order to double the thickness for foam-type insulation, you must now have evidence of the thermal conductivity. This has arisen from some research by BRE that found many of the foam-type insulation materials available were no better insulating than rockwool.

Convention 3.08: If overwriting the default U-values in RdSAP, as well as evidence that the calculation has been carried out by a suitably qualified person, evidence of the materials used in the calculation must be provided. A level 4 NDEA has been added to the list of suitably qualified persons.

Convention 4.09: Information on how to select the correct heating system when there is more than one. This should now cover all scenarios, see the flow chart below.


Convention 6.09: When the only heating in the dwelling is an electric shower, the water heating should be recorded as electric instantaneous rather than no water heating.

Convention 9.05: This now covers all scenarios of single dwelling with PV (house/bungalow), buildings with multiple dwellings (flats/maisonettes) and mixed used buildings (e.g. farms with outbuildings). The key thing to note here is that to assign PV to a dwelling there must be documentary evidence or a generation meter present serving the dwelling in question.

Convention 9.11: Clarifies which transaction type to use for Right-to-Buy and Stock Condition Surveys.

An online CPD module is available that goes into more depth about the convention changes, including various examples and scenarios as well a quiz to help ensure that you have understood the key points.