| Topic | Source |
|---|---|
| The MCS register and its fields | MCS, Find an installer |
| Grant requirements for installers | Ofgem, property owner guidance v5.1 |
| RECC protections | RECC, information for consumers |
| HIES protections | HIES |
| Approved consumer codes | Chartered Trading Standards Institute |
| TrustMark claims | TrustMark, logo misuse |
| Competent person schemes | GOV.UK |
| Banned practices (reviews, trust marks, approval claims) | DMCC Act 2024 Schedule 20, legislation.gov.uk |
| Advertising rulings | Advertising Standards Authority |
| Grant deduction rule | SI 2026/390, legislation.gov.uk |
| Design and sound standards | MCS (MIS 3005-D; MCS 020 a)) |
Why we point you to the source
A checking guide is only useful if you can repeat the check. So each page tells you which register or code to search and what to look for, rather than asking you to take our word for a firm. Registers change as firms join and leave; checking on the day is always better than relying on any list, including an old one of your own.
When a source changes
Codes and registers update their websites, and rules change: in 2026, for example, MCS became the only certification accepted for the grant and the sound standard for permitted development tightened. Each page shows the date it was checked. When a source changes, we recheck the page and update the date. If you spot something out of date, send the link through the form.
What we do not use
We do not use installers' own marketing as evidence, publish reviews, or rely on directories that rank firms. Where a fact could not be confirmed at the source, it is left out.
Which source sits behind which check
The check sheet's ten checks each rest on one or two sources. Certification, the technologies covered and grant registration come from the MCS register. Consumer code membership comes from each code's own member search, and the list of codes accepted for the grant from Ofgem's guidance for property owners. TrustMark claims are checked on TrustMark's site. The rules on approval claims and fake reviews come from the DMCC Act on legislation.gov.uk, and the median prices from the DESNZ scheme statistics on GOV.UK.
The rule itself, not an article about it
Where an official body publishes a rule, we link to the rule rather than to someone else's summary of it. That way the date on our page and the date on the source can be compared directly.