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An Assessor Code of Conduct

What a code of conduct requires of energy assessors, in competence, honesty, independence and care, and how clients can use it.

Published 26 October 2026Evidence checked on 26 October 2026General homes; assessor conduct discussed for UK schemes and EU national schemes in general

The short answer

A code of conduct is the set of behavioural rules that an accreditation scheme requires its assessors to follow, beyond technical competence. It typically covers honesty in recording inputs, care in measurement and calculation, independence from sales interests, confidentiality of client information, proper record-keeping, and fair handling of complaints and corrections. A code matters because technical competence alone does not guarantee trustworthy work: a skilled assessor who inflates inputs, hides a sales interest, or refuses to correct an error breaches conduct even where their method knowledge is sound.

Honesty in inputs is the core conduct duty. An assessor must record what was observed, documented or defaulted, without exaggerating favourable features or minimising unfavourable ones, and must not change inputs to achieve a desired rating. That duty protects every later user of the certificate, from buyers and tenants to enforcement bodies, because a certificate's value lies in its standardised, checkable inputs, not in its flattery. An assessor who is pressed by a client for a better rating should explain the method and refuse to distort inputs, and a client who presses for distortion should understand that they are asking for a breach.

What it means in practice

Independence is a related duty. An assessor who also sells measures, or who is paid by a party with an interest in the outcome, must declare that interest and must ensure that assessment stands on its inputs regardless of it. Where independence cannot be assured, for example where the same person assesses work they installed, the assessment's credibility suffers, and a separate assessor for verification is the cleaner route. Codes often require declaration of interests precisely so that clients can judge credibility, rather than assuming independence that does not exist.

Care and record-keeping complete the conduct picture. An assessor should survey thoroughly, measure rather than guess where measurement is possible, photograph and note evidence, lodge data accurately, and retain records for the scheme's required period. Sloppy measurement, missing photographs, or lodged data that differs from survey notes are conduct issues as well as accuracy issues, because they prevent later checking and correction. A code that requires records is a code that makes accountability possible.

Checks before you act

Before engaging an assessor, ask which scheme and code govern them, and what the code requires on independence, records and corrections. During the assessment, note whether the assessor measures, photographs and asks factual questions, or rushes, assumes and avoids documentation. After receiving the certificate, check inputs you can verify, and raise any concern promptly and in writing, first with the assessor and then with the scheme, following the complaints route for that scheme.

For assessors, a code is also protection. An assessor who follows a code, who records honestly, declares interests, keeps records and corrects errors promptly, can show their work and defend it against unfounded complaints. Conduct that is documented is far easier to defend than conduct that relies on memory, and a code-following assessor builds a reputation that brings repeat work from clients who value trust.

How this differs by place

By place, codes follow schemes. UK assessor codes are set by accreditation schemes, with devolved register implications, while EU certifier codes follow national schemes under the EPBD framework. The principles, honesty, independence, care and records, are shared, but the specific rules, complaint routes and sanctions differ, and a client should check the scheme for the assessor concerned rather than assuming a familiar code applies abroad.

For related professionals, such as retrofit assessors, coordinators and installers, separate codes and scheme rules apply, and a complaint about one role should be judged against that role's code, not an assessor's code. Role-specific codes prevent the common error of blaming an assessor for installation quality, or an installer for a rating.

Mistakes that waste money or time

A common mistake is to treat a code as mere paperwork, and to judge an assessor only on friendliness or price. Conduct shows in measurement, documentation and willingness to correct errors, and those behaviours are observable during and after a visit. Another mistake is to pressure an assessor for a rating, and then to be surprised when a later correction, complaint or enforcement check unravels a transaction built on distorted inputs.

A further mistake is to raise a conduct concern vaguely, without evidence or a named code provision. Schemes investigate specific allegations with evidence, such as a photograph contradicting a recorded input, or a sales interest that was not declared, far more effectively than general dissatisfaction.

Evidence to keep, and what to ask

Keep the assessor's scheme and code reference, the certificate, survey evidence and any correspondence together. That file supports any conduct query and any future assessment.

Questions to ask include: which code governs you, what does it require on independence and records, and how do I raise a concern. Those questions make a code of conduct practical rather than abstract.

Sources and evidence on the record

Evidence basis: Educational guidance in general terms; codes are scheme-specific and must be checked in current scheme guidance. Applies when: You are engaging an assessor and want to know what conduct to expect, or you have a conduct concern

Next on the file

File 15 - Assessors, certificates and evidence Energy Assessors and Certificates What energy assessors do, what certificates prove, and how the evidence around a certificate should be kept and used. File 15 - Assessors, certificates and evidence An Assessor Complaints Process How an assessor complaints process works step by step, what to include, and what outcomes to expect, in general terms. File 15 - Assessors, certificates and evidence Assessor Continuing Development Why assessors must keep learning, what continuing development covers, and how clients can check that an assessor is current.