Changes to RdSAP for Dec. 2014

On the 8th December 2014, the process for creating an EPC is changing. There are now some extra measurements and photos that will be necessary to complete the energy survey, and we are going to run through the key changes here and give you an idea of the implications.

Party walls

The type and length of any partition walls will now need to be measured. In the past, these were ignored because they weren’t considered heat loss, but that isn’t entirely true. Some partition walls are solid, and some have cavities. If the cavity extends up into the loft, then heat can escape like a chimney, funnelling the heat up and out the property.

Part of the reason this is now being included in the assessment is to allow filling of these heat loss party walls. It will mean the assessor needs access to the party wall in the loft to check the wall type.


For older windows in PVC, the gap between the two panes of double glazing must be estimated. Obviously it is difficult to tell this precisely, but the assessor will need to tick a category of 6, 12 or 16mm. This is not required for any windows installed post 2002, or single, triple or secondary glazed windows.

The point of this is to allow the assessor to recommend replacement glazing where applicable in the occupancy assessment, where before old double glazing could not be recommended for replacement.

Pumps and heating controls

Another minor change is the inclusion of pumps in your heating system. It will allow the recommendation of a replacement pumps where appropriate. The other change to heating systems is that time and temperature zone controls that communicate with TRVs are now included, so if you have an intelligent heating system it may mean your rating will improve. Next generation storage heaters can also now be included, along with weather compensators.

Park Homes

There are extensive changes to the way park homes must be lodged. We will be writing a separate blog detailing more about EPC’s with Park Homes.

What do these changes to the EPC process mean for the customer?

So these changes all impact the assessor and it will take longer for the surveys to take place, but what is the impact for the customer (aside from having the EPC assessor in the home for a little longer!) – well to be honest, it should mean a more accurate survey and therefore a more accurate representation of the energy efficiency of the property. We often find that the Government software makes big assumptions, but changes like those mentioned above do improve the accuracy of the reports.

At London-EPC we have put all our assessors through detailed training to ensure they are fully up to speed with the new changes so you can be sure that your assessor is providing you with the best possible service.