TrustMark Quality Assurance

TrustMark Quality Assurance encompasses all work(s) for government funded schemes that require mandated lodgement into the TrustMark Data Warehouse including, but not limited to:

• Energy Company Obligation (ECO)
• Great British Insulation Scheme (GBIS)
• Warm Homes Discount (WHD)
• Warm Homes Plan (WHP)

TrustMark uses a variety of methods to conduct the Quality Assurance of measures lodged in the Data Warehouse. These include a blend of onsite and desktop audits. TrustMark works in collaboration with its Scheme Providers through the sharing of data recorded within the Data Warehouse. This data includes but is not limited to:

• Registered Business performance
• Volumes of work lodged across government schemes

These documents are applicable for work installed under the current version of PAS:2035, PAS:2030, Microgeneration Certification Scheme (MCS) standards delivered under associated government schemes where TrustMark is mandated.

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.