Retrofit Assessors and Retrofit Coordinators: Who Does What

A retrofit coordinator is the professional who takes responsibility for a whole domestic retrofit project. They are described in official guidance as qualified professionals who look at a property's whole energy output, with expertise spanning energy use, planning, compliance and quality assurance¹. In practice the coordinator oversees the project from start to finish, bringing together the right information, an understanding of the risks and coordinated decisions in line with PAS 2035², and covering retrofit design, construction, handover and monitoring³. A retrofit assessor is a different job: the assessor conducts the survey and provides the coordinator with the data required to inform decision-making⁴.

PAS 2035 is the overarching UK retrofit standards framework⁵, developed by the British Standards Institute to govern domestic retrofit work⁶. Where government-funded measures are involved, installations must comply with PAS 2035 and installers must be TrustMark registered or meet equivalent requirements⁷. The standard also fixes where responsibility sits: the retrofit designer is responsible for ensuring that selected products are appropriate and comply with Building Regulations⁷. Competence is set by qualification, with the assessor role calling for a Level 3 qualification in Retrofit Assessment⁶. Traditional or historic buildings are treated separately, typically categorised as high-risk, with adherence to BS 7913: Guide to the Conservation of Historic Buildings and specialised qualifications such as the ABBE Level 3 Award in Energy Efficiency and Retrofit of Traditional Buildings⁸.

For a householder the practical question is when these roles appear. They are required for all domestic retrofit projects seeking to comply with PAS 2035⁹, which in turn is the condition attached to publicly funded and obligation-funded work: under Department for Energy Security and Net Zero schemes, installations must comply with PAS 2035 and installers must be TrustMark registered or meet equivalent requirements¹⁰. Wholly private work paid for out of savings is not automatically inside that system, though some loan and grant schemes impose it as a condition.

The five PAS 2035 roles and what each one owns

The standard sets out minimum standards of qualification, roles and responsibilities for anyone carrying out retrofitting¹³. The division of labour matters because it determines who a householder can hold to account for what.

The coordinator role is central to PAS 2035, protecting homeowners and clients by managing projects in compliance with the standard¹⁵. The intent behind it, as one practising coordinator has put it, is to have complete knowledge of everything that goes on within that property and an involvement in whatever is the right thing to do for that property¹⁵. That is why coordinators are expected to understand building physics, moisture, ventilation, services, improvement planning, quality assurance and the practical realities of delivery². Consultation feedback in Scotland found the same: the role would be key, and would require broad knowledge and practical experience of refurbishment, renovation, whole house retrofit and new build construction⁴.

Heritage work stretches all of this further. For traditional or historic buildings PAS 2035 mandates adherence to BS 7913, the guide to the conservation of historic buildings; such projects are typically categorised as high risk and require professionals to hold specialised qualifications such as the ABBE Level 3 Award in Energy Efficiency and Retrofit of Traditional Buildings¹⁶. The standard recognises the unique nature of heritage buildings and encourages designers to develop solutions that respond to each building individually rather than adopting generic strategies, with designers, coordinators, assessors, contractors and conservation specialists all playing a part¹⁷.

What the assessment and the plan contain

The assessment is the evidence base. PAS 2035 promotes a whole-house approach to reduce the risk of detrimental consequences for the health and comfort of residents, and it requires the production of longer-term retrofit plans¹⁸. That is the essential difference from a single-measure quote: the assessment is meant to describe the building as a system, and the plan is meant to sequence work over years rather than weeks.

An assessment under the standard is not an EPC, though the two are often confused. A domestic energy assessor visits the property in person, inspects insulation, heating systems, ventilation, window glazing and the building's materials, and enters the data into government-approved software to generate the EPC, a method designed to avoid bias; prices vary with location and property size but typically range from £50 to £120¹². A PAS 2035 retrofit assessment goes wider, covering condition, ventilation, moisture risk and occupancy, so the coordinator can weigh risk rather than just score the fabric. The standard is also recognised in building regulations guidance: PAS 2035 is already referenced in the current Approved Document as a means to assess background ventilation in an existing dwelling, and that reference is to be retained in the 2026 edition¹⁹.

Where insulation is being added, guidance in Wales identifies a retrofit coordinator as an example of an appropriately trained person to assess whether an element is suitable before insulating²⁰, repeating earlier advice that for renovations, conversions or a material change of use the person carrying out the work should be appropriately trained in risk assessment and management, for example a retrofit coordinator as identified in PAS 2035²¹. For more detail on what a survey covers, see what is included in a PAS 2035 retrofit assessment and whole house plans.

Where the coordinator fits in the project timetable

The coordinator is not a box ticked at the end. Practitioners argue the coordinator should be involved from the start of the project, with the client, all the way through the scheme¹⁵. Since March 2025 there has been a firmer rule: retrofit coordinators, who manage the design and installation of the measures, are required to physically visit each project site¹¹.

The end of the process is also defined. TrustMark issues a Certificate of Lodgement once the project retrofit coordinator has signed off the project and submits a lodgement²², and the certificate sets out the address at which a measure has been installed or repaired and the type of measure²³. Work and financial protection have to be lodged into the TrustMark Data Warehouse to allow oversight of retrofit activities⁷. That lodgement record is what later underpins a warranty claim or a remediation visit, which is why it belongs in the paperwork to keep.

TrustMark: the register the roles sit inside

TrustMark is the government endorsed quality scheme covering work a consumer chooses to have carried out in their home, and describes itself as the only government endorsed scheme for domestic trades¹⁴. It was chosen following the Each Home Counts review as the route to give homeowners reassurance and protection from rogue traders¹⁴. It operates under licence from the Department for Business and Trade and is overseen by an independent board, and is a not-for-profit social enterprise funded by a small fee from scheme providers for each registered firm²⁵. The scheme is operated by TrustMark (2005) Limited, a company registered in England and Wales with company number 05480144²³.

The oversight is layered. The scheme is underpinned by Framework Operating Requirements, a Customer Charter and a Code of Conduct that member companies must follow, with initial and ongoing assessment and surveillance visits¹⁴. TrustMark audits scheme providers every year²⁵, and for works lodged in its Data Warehouse carries out both desktop monitoring and risk-based inspections on works by registered businesses²⁶. It has the right to suspend or remove registered businesses²⁵, is a member of the Dispute Resolution Ombudsman²⁶, and offers a national Trading Standards Approved membership option through its primary authority partner, Buckinghamshire and Surrey Trading Standards²⁶. One independent assessment recorded 35 licensed scheme providers and over 15,000 registered businesses, with installers required to be MCS certified for low carbon heat and renewables and PAS 2035 certified for energy efficiency measures¹⁶. All publicly funded work in this sector, and work under the Energy Company Obligation, requires TrustMark registration¹⁶. TrustMark states there should be no premium for using a registered business, and suggests obtaining a minimum of three quotes for any planned work²⁵.

Where remedial checks follow, a letter or a caller should quote a unique measure reference number so a householder can confirm it is genuine, and identification can be requested at the door²⁸. TrustMark's helpline runs Monday to Friday, 9am to 5pm on 0333 555 1234, with calls costing up to 16p a minute from a landline or between 3p and 65p a minute from a mobile²⁸. TrustMark also lists funding routes and has partnered with the escrow service Transpact to provide payment protection for consumers and traders²⁹.

How the four nations differ

The standard is UK-wide but the route to a coordinator is not. TrustMark covers domestic work only³⁰, and the Scottish Government has said it will work with TrustMark to develop a quality assurance scheme for Scotland enabling domestic consumers, including private sector landlords, to access approved suppliers in accordance with PAS 2035 and PAS 2030 standards³⁰. Suppliers approved under TrustMark or MCS are subjected to a thorough screening process including checks against Trading Standards systems, with sanctions up to suspension or removal³⁰.

Scotland has also proposed a different role structure of its own. The HEETSA process is set out as recognising four distinct but complementary roles: a Retrofit Project Manager, a Retrofit Advocate, a Retrofit Consultant and a Retrofit Assessor³¹. Scottish policy work has been explicit that retrofit assessors should be independent and regulated to ensure unbiased recommendations tailored to each property's needs rather than commercial interests³¹.

Welsh loan terms are specific: the borrower must have instructed a retrofit coordinator registered with the UK Government's TrustMark scheme, who will provide end-to-end support throughout the selection and installation of the eligible measures at the property³⁶. The Retrofit Coordinator Grant requires the applicant to instruct a coordinator registered under TrustMark and approved by the Development Bank of Wales within 14 days of the date of the grant letter, and where the invoice exceeds the total grant amount the applicant pays the difference³⁴. Working under a scheme also means accreditation: a coordinator needs TrustMark registration, PAS 2035 compliance and Retrofit Coordination trade accreditation¹.

In England, provision is inconsistent, with only parts of the country able to reach local services³⁵. Some local models exist: Cosy Homes Oxfordshire operates as a one-stop shop for all home retrofit needs, with a retrofit coordinator acting as a single point of contact for the homeowner throughout the process³⁷. Householders can compare what is available near them in regional retrofit advice services and the national advice pages for England, Scotland, Wales and Northern Ireland.

The capacity problem behind the qualifications

Numbers constrain everything above. A parliamentary committee has concluded that retrofitting the UK's homes will require at least 100,000 more trained workers³⁸. On the coordinator side, consultation responses in Scotland noted that the approved course for the retrofit coordinator was at that time available from only one education provider in England⁴. One training provider reported having trained over 1,800 retrofit coordinators nationwide by April 2022³⁹. Entry routes remain demanding: a Level 3 qualification in a built environment discipline, work experience in the building industry and strong customer service skills³⁷.

This matters practically. Where coordinators are scarce, waiting times lengthen, and scheme-funded work is the priority claim on their time. Householders planning privately funded work in stages should expect availability, not price alone, to set the pace.

Where the independence claim breaks down

The clearest limit on the whole system is structural. The Public Accounts Committee recorded that retrofit assessors and retrofit coordinators can be appointed and contracted by the installer they are assessing, and the department agreed that there is not enough independence between these roles under PAS 2035¹¹.

That sits awkwardly beside the Scottish position that assessors should be independent and regulated so recommendations follow the property rather than commercial interests³¹, and beside the Welsh description of an independent coordinator overseeing all works to ensure they are safe, high quality and fully compliant³³. The documents describe an intention that the current standard does not always deliver. Where a coordinator is paid by the installer, a householder holds a compliance record rather than an independent second opinion.

The version of the standard in force is also moving: Ofgem's ECO4 delivery guidance updated references from PAS 2035:2019 to PAS 2035:2023 throughout⁴⁰. It is worth checking which version a quotation cites.

What this means for a household's energy independence

Retrofitting means making changes to existing buildings to reduce energy use and therefore carbon emissions⁴¹, and the case made for doing it at scale is that it permanently reduces energy bills, improves energy security and cuts carbon emissions³⁵. Coordination is the mechanism that makes those reductions durable rather than accidental: PAS 2035 provides a framework for managing risk, balancing competing priorities and delivering better retrofit outcomes¹⁷, and its whole-house approach exists to reduce the risk of detrimental consequences for the health and comfort of residents¹⁸.

The dependence that remains is worth naming. A coordinated retrofit reduces a home's draw on gas and imported electricity, but it inserts new dependencies: on a manufacturer's guarantee, on a scheme provider, on TrustMark's lodgement record, on the installer's continued trading, and, where funding is involved, on the terms of a public scheme that can change. The 25-year guarantee on certain ECO measures²⁴ is only as good as the body standing behind it, and the remediation of substandard solid wall insulation²⁷ shows that quality failure is a live risk rather than a theoretical one. For planning the longer arc of work, see planning a route to household energy independence and the wider getting started guide.