Accreditations
Accredited by Elmhurst, ECMK and Quidos. Registered with TrustMark.
Anyone can call themselves an energy consultant. Only an accredited assessor can lodge an Energy Performance Certificate. Here is what our accreditations mean, and how to check every one of them yourself.
Why accreditation matters
By law, an EPC can only be produced by an energy assessor who belongs to a government-approved accreditation scheme. The scheme is what stands behind the certificate. It confirms that the assessor is qualified, requires them to hold insurance and keep their training up to date, and audits a sample of their work.
Since 1 October 2026 those audits have had a sharper edge. Under new minimum evidence requirements, an auditor must be able to reproduce any certificate from the assessor's own photographs, measurements and notes.
Elmhurst Energy
Elmhurst describes itself as the UK's largest independent provider of energy assessment, retrofit and property professional training. Its accreditation schemes cover domestic and non-domestic energy assessors, Retrofit Assessors and Retrofit Coordinators.
We display two Elmhurst marks: the Approved Energy Assessor logo, and the Quality Promise seal for accredited members.
ECMK
Established in 2003, ECMK is one of the original approved energy accreditation schemes in the UK. It accredits domestic and non-domestic energy assessors and operates a TrustMark approved scheme for Retrofit Assessors and Retrofit Coordinators.
We display the ECMK Accredited Member mark.
Quidos
Quidos is a government-approved accreditation scheme that has been based in Bath since 2006. It accredits domestic energy assessors, non-domestic assessors at levels 3, 4 and 5, and retrofit professionals, and it requires members to complete continuing professional development every year.
TrustMark
TrustMark is the only Government Endorsed Quality Scheme for work carried out in and around the home. It is a not-for-profit organisation that has operated since 2005 under a licence from the Department for Business and Trade, and it covers more than 18,000 registered businesses.
Registered businesses commit to standards of technical competence, customer service and trading practices, and must follow TrustMark's Code of Conduct and Customer Charter. Anyone working on a PAS 2035 retrofit project, including Retrofit Assessors and Retrofit Coordinators, has to be registered.
How to check us
You should not have to take our word for any of this.
- Search the government's assessor register. The find an assessor service on GOV.UK lists accredited assessors in England, Wales and Northern Ireland by postcode or by name.
- Look at any certificate we have lodged. Every EPC shows the assessor's name, their accreditation scheme and their assessor number.
- Search TrustMark. The TrustMark website has a directory of registered businesses.
- Ask us. We will give you our accreditation numbers before you book.
One thing to know when you search: Retrohaus Energy Consultancy is a trading name of Build Net Zero Limited, company number 16646393, so some registers list us under the company name.
If something is not right
Tell us first. Most concerns are about a rating that looks wrong, and they are usually settled by going through the evidence together. If we have made a mistake, we will correct it.
If you are still unhappy, GOV.UK's guidance is to contact the assessor's accreditation scheme, whose details appear on your certificate. The scheme will review the assessment independently. For retrofit work, TrustMark requires every registered business to have a clear, fair and transparent complaints process, with access to dispute resolution if that fails.
Sources: GOV.UK, Get a new energy certificate; Elmhurst Energy; ECMK; Quidos; TrustMark. Scheme descriptions are taken from each organisation's own website, checked October 2026. Logos are shown as supplied to accredited members.