TrustMark Quality Assurance

If a measure is identified as non-compliant before 1st January 2026, the remediation timeframe will start on 1^st January 2026. 

For measures identified as non-compliant on or after 1st January 2026, the remediation timeframe will begin from the date the Registered Business is notified of the non-compliance. 

Remediations will be valid only if they occur before the relevant deadline. TrustMark will not accept late remediations as valid.  

 

Non Compliance Category	CoL Void Timescales
Remediation deadline for non-compliant measures, identified before 1st January 2026	8 weeks from 1st January 2026
Remediation deadline for non-compliant measures, identified on or after 1st January 2026	8 weeks from when the installer is notified of the non-compliance. TrustMark has 2 weeks to review evidence before initiating a void
CAT 1	24 hours to make safe, as a minimum

A remediation deadline extension option will be available for legitimate circumstances, options can include: 

• Registered Business actively trying to remediate and engaging in policy
• Large numbers of non-compliance generate backlog for the Registered Business 
• Alternative Retrofit Coordinator (RC)/ Registered Business being sought by supply chain
• Guarantee provider engaged  

All extensions will be capped by remediation deadlines for the relevant scheme (see Table below). 

Extensions will only be agreed on a case-by-case basis by TrustMark. 

TrustMark will void where remediation was not successful due to non-access and the no access policy evidenced. 

Key fixed dates below:

What	When
GBIS - Final remediation deadline	1st June 2026
GBIS - Final determination	1st December 2026
ECO4 - Final remediation deadline	1st February 2027
ECO4 - Final determination	1st July 2027

 

Ofgem has published new versions of their ECO4 and GBIS guidance documents. A full list of changes is available in the summary of updates document on each publication page:

ECO4 Delivery Guidance

ECO4 Supplier Administration Guidance

GBIS Delivery Guidance

GBIS Supplier Administration Guidance

Live from 18/11/24

This document outlines the responsibilities and requirements for Retrofit Coordinators (RC) and other qualified professionals overseeing energy efficiency installations under Publicly Available Specification (PAS) 2030:2023.

It emphasises a risk-based approach, mandatory site visits for measures such as External Wall Insulation (EWI), Internal Wall Insulation (IWI), Room-in-Roof Insulation (RIRI), Underfloor Insulation (UFI), Park Home Insulation (PHI), and Flat Roof Insulation (FRI), and the qualifications needed for those conducting site visits.

It also details the use of digital evidence, conditions under which physical inspections are required, and the process for confirming sufficient evidence before project lodgement.

Live from 23/09/25

The EPR Conventions Working Group, comprising of TrustMark, Ofgem, Retrofit Assessment Scheme Providers (Elmhurst, ECMK, Quidos, Sterling), and wider industry stakeholders has updated the Energy Performance Report (EPR) Variation Convention to reflect the transition from RdSAP 9.94 to RdSAP 10.

These changes will apply only to new projects with retrofit assessments conducted on or after 10th November 2025

Key updates include revised requirements for the pre- and post-installation recording of ventilation, aligned with the latest ECO4 and GBIS regulations. These changes are designed to ensure consistency, compliance, and improved quality across retrofit assessments.

We strongly encourage all assessors to familiarise themselves with the updated conventions to ensure readiness ahead of the implementation date.

Ventilation Upgrades

Where ventilation in a property has been upgraded as a part of the project, then the updated ventilation system must be reflected in the post EPR, even though Ventilation is not an ECO4/GBIS eligible measure.

Air Tightness Testing

All airtightness testing must be conducted by an appropriately trained Level 1 or Level 2 airtightness tester who is registered with a government-approved Competent Person's Scheme.

The testing itself must be carried out using calibrated equipment in accordance with CIBSE TM23. The building preparation and testing procedure to be used is also detailed in CIBSE TM23.

For an airtightness test to be valid and used within an RdSAP lodgement, it must be lodged to the registered Competent Person's Scheme, with the resultant certificate provided as documentary evidence for audit purposes.

Where an airtightness test is used in an ECO4/GBIS project, this must be done for both the pre and post EPR.  If only used on the Pre or Post EPR, the project will be non-compliant.

If you have any questions, please contact your Retrofit Assessor Scheme Provider.

Live from 01/02/23

In December 2022, TrustMark (on behalf of Retrofit Assessor Scheme Providers) published the Energy Performance Report (EPR) conventions to be applied specifically to ECO4 & GBIS projects.