ECO2 cavity wall U-value checklist

Publication date
3rd October 2016
Information types
Policy areas

On 8 February 2016 we launched an ECO2 consultation on requirements for overwriting U-values for cavity wall insulation (CWI) measures. Our final policy includes the introduction of a cavity wall U-value checklist which is required for all CWI measures with overwritten U-values installed from 1 June 2016. For further details about how we came to our final policy please see our consultation response document.   

The cavity wall U-value checklist is designed to:

  • collate the information needed for cavity wall insulation (CWI) wall U-value calculations
  • allow the relevant operative(s) to confirm that the data provided is accurate to the best of their knowledge
  • allow the relevant operative to confirm that the requirements described in RdSAP 2012 (9.92) have been met.

This checklist also contains further information and guidance on our requirements for CWI measures with overwritten U-values.

Update 6 May 2016

Please note that on 6 May 2016 we published an updated version of our response document. This was to provide additional clarity around how a U-value should be overwritten where it exceeds the relevant threshold for CWI measures. We have reflected this amendment in the text accompanying the cavity wall U-value checklist. These amendments do not introduce any changes to our policy.

Update 3 October 2016

On 3 October 2016, we published an updated version of our cavity wall U-value checklist. This update reflects changes to RdSAP convention 3.08, as shown in RdSAP conventions v9.0. These changes came into effect from 1 October 2016. 

The change has expanded those treated to have suitable expertise and experience to produce U-value calculations to include Level 4 Non-Domestic Energy Assessors (England & Wales) and/or New Build Scotland Non-Domestic Energy Assessors. 

Operatives with these qualifications will now be able to complete the checklist where the U-value is below the threshold for the relevant age band. Where a U-value exceeds the relevant threshold, they can produce a calculation where the inputs are based on either construction details and specifications or a core sample tested in a laboratory. We have reflected this amendment in the cavity wall U-value checklist.