Retrofit Assessors and Retrofit Coordinators: Who Does What

A retrofit coordinator is a qualified professional who looks at your property's whole energy output, with expertise covering energy use, planning, compliance and quality assurance¹. A retrofit assessor is the person who gathers the data about your home and hands it to the coordinator to inform decisions². Those two roles, plus a designer, an installer and an evaluator, are the five roles the UK retrofit standard PAS 2035 defines for anyone carrying out retrofit work³.

The reason a householder meets these people at all is that PAS 2035, introduced in 2019 as a framework for best practice in the energy retrofit of domestic properties, has to be managed by a qualified retrofit coordinator⁴. Retrofit coordinators are required for all domestic retrofit projects in order to comply with the standard⁵, and they must be registered with the UK Government's TrustMark scheme⁶. If your insulation or heating work is grant-funded, the funder will usually insist on both.

Retrofitting itself means making changes to existing buildings to reduce energy use and therefore carbon emissions⁷. The roles exist to make sure those changes are done as a coherent whole rather than as disconnected jobs, and this page explains who does what, what the paperwork contains, how the rules differ across the four nations, and where the system's guarantees are weaker than they sound.

PAS 2035's five roles and their responsibilities

PAS 2035:2019, now referenced as PAS 2035:2023 in current delivery guidance¹², sets out guidelines for energy efficiency contractors, laying down minimum standards of qualification, roles and responsibilities for anyone carrying out retrofitting¹³. The standard names five roles: retrofit coordinator, assessor, designer, installer and evaluator³.

The retrofit assessor plays a key role in conducting assessments and providing the retrofit coordinator with the data required to inform decision-making². The assessor is the person who visits your home first. A Scottish Government review of retrofit assessment describes the ideal as four distinct but complementary roles in the design and delivery of retrofit projects: a Retrofit Project Manager, a Retrofit Advocate, a Retrofit Consultant and a Retrofit Assessor¹⁴. That model goes further than PAS 2035, but it shows the direction of thinking: assessment, advice and project management are being pulled apart into separate jobs so that no one person both recommends and sells the work.

The retrofit coordinator is the project's manager. Development Bank of Wales describes retrofit coordinators as qualified professionals who take a look at your property's whole energy output, a bit like an energy audit, with expertise on energy use, planning, compliance and quality assurance¹. Consultation feedback gathered by the Scottish Government was that this role would be key, and would require broad knowledge and practical experience in working in refurbishment, renovation, whole house retrofit and new build construction². The coordinator provides end-to-end support throughout the selection and installation of the measures at the property⁶.

The designer specifies what is actually installed, the installer fits it, and the evaluator looks at whether the finished work delivered what was promised. PAS 2035 and its installation standard PAS 2030 were subsequently integrated into the UK-government endorsed TrustMark quality assurance scheme, with Green Deal Approved installers transitioning over³.

Inside the assessment and the plan

The retrofit assessment is the data-gathering stage, and its contents matter because everything downstream is built on it. The assessor collects information about the property and passes it to the coordinator, who uses it to inform decision-making². A fuller account of what a PAS 2035 assessment covers is on our page what is included in a PAS 2035 retrofit assessment, and the broader landscape of assessment types is covered in home energy assessments.

The assessment feeds a whole house plan. PAS 2035 was introduced in 2019 as a clear framework for best practice in the energy retrofit of domestic properties, and under it the project has to be managed by a qualified retrofit coordinator so the householder does not have to manage the process themselves⁴. The plan that results sets out the measures in an order that respects the fabric of the building, which is the approach our fabric first and order of energy improvements pages explain in detail.

Two things are worth knowing about the assessment stage. First, Retrofit Assessors should be independent and regulated to ensure unbiased recommendations tailored to each property's needs rather than commercial interests¹⁴. That is the stated principle; how well it holds in practice is another matter, covered later on this page. Second, the assessment is not just an EPC. The skills requirements consulted on by the Scottish Government relate to retrofit installers, energy assessors, designers, advisors, evaluators and retrofit coordinators, a wider set of disciplines than a single energy assessment¹⁵.

The coordinator's place in the project schedule

The coordinator is appointed early and stays to the end. Under the Green Homes Wales loan terms, the borrower must have instructed a Retrofit Coordinator registered with the UK Government's TrustMark scheme, and that coordinator provides end-to-end support throughout the selection and installation of the eligible measures at the property⁶. Wales makes the timing explicit in its Retrofit Coordinator Grant: the applicant must instruct a coordinator registered under TrustMark and approved by the Development Bank of Wales within 14 days of the date of the RC Letter¹⁶.

The coordinator's sign-off is what triggers the paperwork a householder keeps. TrustMark will issue a Certificate of Lodgement once the project retrofit coordinator has signed off the project and submitted a lodgement¹⁷. A certificate of lodgement is a document which sets out the address at which a measure has been installed or repaired and the type of measure¹⁸. Work and financial protection also needs to be lodged into the TrustMark Data Warehouse to allow oversight of retrofit activities³. Our page on the paperwork to keep from every energy improvement explains why these documents matter later, for guarantees and for selling the house.

Since March 2025, it is a requirement for retrofit coordinators, who manage the design and installation of the measures, to physically visit each project site¹⁰. That change came out of parliamentary scrutiny of retrofit oversight, and it means a coordinator who never appears at your home is not meeting the current requirement.

TrustMark and the register holding these roles

TrustMark is the scheme operated by TrustMark (2005) Limited, a company registered in England and Wales¹⁸, and it is a government-endorsed quality scheme¹⁹. To carry out work under the Welsh schemes, a retrofit coordinator must be TrustMark registered and PAS 2035 compliant, along with holding Retrofit Coordination trade accreditation¹. TrustMark registration is also the gate for government incentive schemes: to qualify for schemes such as the Green Homes Grant, installation contractors must be TrustMark registered, and if work is funded by certain energy efficiency schemes the installation contractor must register the installation in the TrustMark Data Warehouse²⁰.

TrustMark is responsible for ensuring installers comply with PAS and MCS standards and that appropriate guarantees are in place under the Great British Insulation Scheme²¹, and it reviews the quality assurance process with full oversight of monitoring for ECO measures²². Any supplier approved under the TrustMark scheme or MCS is subjected to a thorough screening process including checks against Trading Standards systems, with monitoring and possible sanctions including suspending or removing the company from the scheme²³. Ministers have advised householders to use builders registered with TrustMark, which is a trusted scheme, to ensure that work is done properly²⁴.

The oversight is not theoretical. Routine checks carried out by TrustMark, the independent body which oversees tradespeople working in homes, have uncovered substandard solid wall insulation²⁵. As of November 2025, 22 installers had been fully reinstated after meeting requirements on TrustMark's robust six-point plan, including full remediation of the problems identified¹⁰. Work lodged through TrustMark carries a minimum two-year warranty for work, and a minimum 25-year guarantee for certain measures installed under the ECO¹¹.

What lodging the work through TrustMark gives a householder:

• A certificate of lodgement, setting out the address at which a measure has been installed or repaired and the type of measure¹⁸
• A minimum two-year warranty for the work¹¹
• A minimum 25-year guarantee for certain measures installed under the ECO¹¹
• Oversight of the work in the TrustMark Data Warehouse, allowing monitoring of retrofit activities³
• Access to dispute management through TrustMark's framework of operating requirements²⁶

If something goes wrong, TrustMark operates a robust framework of operating requirements, including dispute management²⁶. The Department for Energy Security and Net Zero has nominated TrustMark to directly support customers of the closed CES scheme, and householders can call TrustMark on 0333 555 1234, email disputes@trustmark.org.uk, or fill out the online support form on TrustMark's website²⁷.

Differences across the four UK nations

The standard is UK-wide but the funding routes are not. PAS 2035 is the overarching UK retrofit standards framework²⁸, and PAS 2035 is already referenced in the current version of the Approved Document as a means to assess background ventilation in an existing dwelling, a note that will be retained in the 2026 edition²⁹. In England, Approved Document L consultation text says the person carrying out assessment work should be appropriately trained in risk assessment and management, for example a Retrofit Coordinator as identified in PAS 2035³⁰, and earlier consultation text on Part L made the same point for renovations, conversions or material change of use³¹.

Wales goes furthest in funding the roles. Green Homes Wales provides fully funded access to a Retrofit Coordinator to create a detailed home assessment²⁸, and an independent Retrofit Coordinator oversees all works to ensure they are safe, high quality and fully compliant³². The Retrofit Coordinator Grant is offered to the owners of eligible properties, with properties outside of Wales excluded¹⁶, and if the amount required to pay the coordinator's invoice is more than the total grant amount, the applicant must pay the difference¹⁶. The grant terms are governed by the laws of England and Wales¹⁶. Our page on Nest, the Welsh Government home energy scheme covers the wider Welsh offer.

Scotland has not adopted the TrustMark framework wholesale. The Scottish Government has said it will work with TrustMark to develop a quality assurance scheme for Scotland which will enable domestic consumers, including private sector landlords, to access approved suppliers in accordance with PAS 2035/30 standards²³, and that the UK Government-endorsed TrustMark quality assurance framework will be considered³³. A Scottish consultation on skills requirements for energy efficiency and low carbon heating covers retrofit installers, energy assessors, designers, advisors, evaluators and retrofit coordinators¹⁵. Advice routes also differ: our pages on free home energy advice in England, Scotland, Wales and Northern Ireland set out what each nation offers.

The capacity gap underlying the qualifications

The qualifications are demanding, and the workforce is thin. Retrofit coordinators must hold Level 3 qualifications in built environments and a Level 5 Diploma in Retrofit Coordination and Risk Management⁸. Retrofitting the UK's homes will require at least 100,000 more trained workers³⁴, and a Scottish Government consultation analysis noted that the approved course for the Retrofit Coordinator was currently only available from one education provider in England².

That single-provider bottleneck matters for householders in two ways. First, it limits how many coordinators exist, which pushes up lead times and, where the coordinator is not grant-funded, the price. Second, it concentrates training in England, so households in Scotland, Wales and Northern Ireland face longer waits or travel costs for the professionals their schemes require. The Scottish skills consultation exists precisely because the Scottish Government is trying to build its own pipeline¹⁵.

The volume of work already flowing through the system gives a sense of scale. There were around 14,700 Warm Homes: Local Grant measures lodged in the TrustMark data warehouse up to the end of July 2026, covering around 6,700 households³⁵. Each of those lodged measures represents a coordinator sign-off, an assessment and a design, on top of the ECO and GBIS work going through the same registered professionals.

When independence claims fall short

The principle is that assessors and coordinators are independent. The reality is weaker. Under PAS 2035, retrofit assessors and retrofit coordinators can be appointed and contracted by the installer they are assessing, and the Department for Energy Security and Net Zero has agreed that there is not enough independence between these roles under the relevant standard¹⁰. That admission came from a parliamentary committee's scrutiny of retrofit oversight, the same process that produced the mandatory site visits.

The same scrutiny found that neither TrustMark nor DESNZ have been able to provide minutes of meetings which took place between 2022 and 2024¹⁰, which limits how much the public record can show about how the framework was policed during that period. The uncovering of substandard solid wall insulation through TrustMark's routine checks²⁵, and the subsequent six-point remediation plan under which 22 installers were reinstated by November 2025¹⁰, demonstrate both that failures happen and that the register does catch them.

For a householder, the practical point is simple: ask who employs the assessor and the coordinator. If the answer is the installer who will sell you the measures, the independence the standard is meant to provide is not there in your project, whatever the framework says in principle.

Implications for household energy self sufficiency

A well-run retrofit under PAS 2035 moves a household a long way towards energy independence: a whole-house plan, measures installed in the right order, work lodged with guarantees of up to 25 years on certain ECO measures¹¹, and a paper trail that survives changes of occupier. The coordinator's job is to make the retrofit coherent, which is the difference between a home that genuinely needs less energy and one with expensive measures that do not work together.

But the dependence that remains is real, and it is worth naming. The household depends on the coordinator's competence and on a qualification pipeline that currently runs through a single English education provider². It depends on TrustMark, a private company operating a government-endorsed register¹⁸, for dispute resolution and guarantee enforcement. It depends on the funder's rules, which differ by nation and can change: the ECO scheme's closure left households needing support, with TrustMark nominated to directly support affected customers²⁷. And where the coordinator is paid by the installer, the household depends on the goodwill of a chain in which no one is paid to say "do not buy this".

None of this is an argument against using the roles. Where work is grant-funded, a TrustMark-registered, PAS 2035-compliant coordinator is usually a condition of the money, and the guarantees that come with lodgement are not available to households that go outside the framework. The argument is for going in with clear expectations:

1. Verify the coordinator's TrustMark registration before appointing them⁶.
2. Ask who employs the assessor and the coordinator, and get the answer in writing¹⁰.
3. Insist on the coordinator's site visit, required since March 2025¹⁰.
4. Keep the certificate of lodgement issued at sign-off¹⁷.

Those habits are what turn a framework designed to protect households into protection that actually lands. For the wider picture of how retrofit fits a route to self-sufficiency, see planning a route to household energy independence, and for what the whole exercise costs, what a whole-house retrofit costs in the UK.