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Every business on this register is checked against the public MCS installer search and the Companies House register. That check happened on 16 September 2026 for the MCS side. We link directly to both sources on every listing so you can re-check them yourself, on today's date, rather than trusting our check date alone.
The two sources we check
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MCS certification confirms the installer is certified for a specific heat pump technology; Companies House confirms the business is a real, currently registered company. Neither source tells you whether a specific job will be done well — that's what quotes, references and your own judgement are for.
The MCS installer search is the UK's certification register for microgeneration technologies, including air source, ground source and water source heat pumps (ASHP, GSHP, WSHP). Certification is issued per technology, not per business as a whole, and it can be added, allowed to lapse, or renewed. We record which technologies were listed against each installer on the date we checked, and we link to their live profile so the current status is always one click away.
The Companies House register confirms a company exists, its incorporation date, and whether it is currently active, dissolved or in another formal status. Sole traders and partnerships without a registered company won't appear here, which is why we don't treat a blank Companies House field as a red flag on its own.
What installers say about themselves
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Brands, accreditations, service areas and years trading are self-reported claims taken from an installer's own website — we did not independently verify them. Every such claim is written as a claim (“states on its website that…”) and linked to the page it came from, never presented as a fact we stand behind.
Where a business's own website names the brands it installs, the accreditations it holds beyond MCS, the areas it covers, or how long it has been trading, we record that — attributed and linked, exactly as written. This is deliberate: what a business says about itself is useful information, but it is not the same category of fact as an entry in a public register, and we don't want the two blurred together.
What absence from the MCS search means — and doesn't
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Not appearing on the MCS installer search on a given date is not proof a business lacks certification. Some installers work through umbrella or parent-company MCS certifications that don't list every trading name individually, and search results can lag real-world changes. The only phrasing we use for this is “not found on the MCS installer search as of [date]” — nothing stronger, and nothing that describes a business's certification status either way.
This is one of the more easily misread parts of the MCS system. A business can be legitimately certified while trading under a name, or through a corporate structure, that the search doesn't surface directly. Where we couldn't confirm a listing against the search, we say exactly that and nothing more — we don't infer the opposite.
How we assign a borough
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Borough is derived from an installer’s postcode outcode — the first half of the postcode, such as ‘KT3’ — via the public postcodes.io lookup, not the exact address, so it is approximate. Some outcodes straddle two London boroughs; where that happens the borough shown may not match the specific business address exactly.
This matters most for postcode districts that sit on a borough boundary — for example SE1 spans Southwark and Lambeth, and KT3 spans Kingston upon Thames and Merton. We correct individual listings when we can confirm the right borough for that specific business, but the underlying method works at outcode level, not address level, so treat the borough shown as a strong approximation rather than a certified fact.
The limits of this register
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This register reports what public sources say on the date they were checked; it does not inspect workmanship, verify insurance, or rank installers by quality. A listing is not a recommendation. Always get your own quotes, ask for references, and check current certification directly with MCS before committing to any work.
We hold no reviews, ratings or review counts on this site, by design — see our About page for why. Ordering throughout the register is alphabetical within each borough. Nobody pays for a listing or for position.
Correcting or removing a listing
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If a detail here is wrong, out of date, or you want a listing removed, tell us and we'll act on it. Use Claim / Correct a listing to submit a correction with its source, confirm ownership of a listing, or request removal outright — removal requests are honoured without argument.