Solar Installer Accreditations Explained: MCS, RECC & Questions to Ask

MCS: the certification that matters most

MCS (the Microgeneration Certification Scheme) is the foundation accreditation for solar. It certifies that an installer and the products they fit meet recognised standards, and it is the credential the rest of the system depends on. Critically, an MCS certificate is required to claim Smart Export Guarantee payments: without it you cannot be paid for the electricity you export, which removes one of the main financial returns from solar. MCS certification is granted per technology, so an installer must hold solar PV certification specifically. After installation you should receive an MCS certificate, which you will need to register for an SEG tariff. You can verify any installer's certification on the MCS website before you hire them. If a company is not MCS-certified for solar PV, that is reason enough to look elsewhere.

RECC and HIES: consumer protection codes

A consumer protection code sits alongside MCS and protects you, the buyer. The two relevant to solar are RECC (the Renewable Energy Consumer Code) and HIES (the Home Insulation and Energy Systems scheme). Both are approved consumer codes that set standards for sales conduct, contracts and complaints, and both provide deposit protection, workmanship guarantees and independent dispute resolution if something goes wrong. Installers usually belong to one or the other. Membership is not optional flair: it is a condition of MCS certification, so any properly accredited firm will be a member of one of these codes and can give you its membership number. The protection matters most in the unlikely event your installer ceases trading, when an insurance-backed guarantee through the code can cover outstanding warranty work.

NICEIC and electrical competence

A solar installation is electrical work, so the competence of the electrician matters. NICEIC and NAPIT are the main bodies that register and assess electrical contractors in the UK. Membership shows that an installer's electrical work is regularly inspected against the wiring regulations and that they can self-certify their work as compliant. Solar connects to your home's consumer unit and the grid, so safe, certified electrical work is not a nice-to-have. While MCS certification already requires competent electrical work, seeing NICEIC or NAPIT registration is additional reassurance that the firm meets recognised electrical standards. Ask whether the installer's own staff or a subcontractor carries out the electrical connection, and confirm they will issue an electrical installation certificate on completion.

TrustMark and government-endorsed quality

TrustMark is the government-endorsed quality scheme for work carried out in and around the home. A TrustMark-registered business has been checked against standards covering technical competence, customer service and trading practices. For solar, TrustMark registration is often required to access certain grant-funded schemes, so it carries practical weight if you are applying for funding such as the Warm and Well programme or ECO4. TrustMark is broader than solar alone, so treat it as a general trust signal that complements, rather than replaces, MCS. The strongest installers will hold MCS certification, belong to a consumer code, register their electrical work and carry TrustMark registration. Each accreditation covers a different angle, and together they tell you the firm takes quality and consumer protection seriously.

How the accreditations fit together

It helps to see what each accreditation actually does, because their names are easy to confuse. The table below summarises the role of each for a solar buyer.

A checklist of questions to ask before you sign

1. Are you MCS-certified for solar PV? What is your certificate number?
2. Which consumer code do you belong to, RECC or HIES?
3. Are you registered with NICEIC or NAPIT for electrical work?
4. Are you TrustMark-registered, and is that needed for any grant I am applying for?
5. Will I receive an MCS certificate and electrical certificate on completion?
6. How is my deposit protected, and is there an insurance-backed guarantee?

How we vet the installers we work with

We are an independent comparison service, and we hold none of these accreditations ourselves because we are not an installer and never carry out work. What we do is apply them as a filter. We only connect homeowners with installers who hold the relevant accreditations such as MCS, so you start your comparison from a shortlist of firms that already clear the bar. You still verify and choose for yourself, with all the questions above, but you are not sifting the whole market alone. Tell us about your home and we will match you with vetted, accredited local installers, free and with no obligation.

How to verify each accreditation yourself

Every accreditation body maintains a public register you can search for free, and checking takes only a few minutes per installer. Before you sign a contract or pay any deposit, open the relevant register, type in the company name or certificate number, and confirm the listing is current and covers the right technology. Registers update regularly, so a live entry is far more reliable than a logo on a website or a claim in a sales call. Logos can be copied from the internet and placed on any page. A register entry cannot be faked. If an installer resists giving you a certificate number, or tells you to trust the logo on their van, treat that as a reason to check rather than a reason to skip the step. The five minutes you spend verifying could save you thousands in lost SEG income or unprotected deposits.

1. MCS: search the official MCS register at mcscertified.com by company name or certificate number. Confirm the listing shows solar PV as a certified technology and that the certificate status is current, not suspended or withdrawn.
2. RECC: use the member directory on recc.org.uk. Search by company name and confirm active membership. The listing will show what technologies the membership covers.
3. HIES: check the member directory on hies.co.uk. Enter the installer name and verify their membership is live and covers solar PV installations.
4. TrustMark: search the TrustMark register at trustmark.org.uk by company name or postcode. Check the firm is listed, that the registration is current, and that it covers the relevant trade category.
5. NICEIC or NAPIT: search the NICEIC register at niceic.com or the NAPIT register at napit.org.uk. Confirm the firm appears as a registered contractor for domestic electrical installation work.

Accreditation red flags: how to spot fakery

Most solar installers are genuine, but a small number misrepresent their accreditation status to win work from homeowners who do not check. The consequences are serious: you may lose your right to Smart Export Guarantee income, have no deposit protection, or be left without recourse if something goes wrong. A lapsed MCS certificate means the firm was once certified but is not today, so it no longer qualifies you for SEG payments. Some firms claim their certification is pending, which is not a valid status for work they carry out now. Others use a certificate number belonging to a different company, typically a partner or former employer, which is not transferable. Watch for firms certified for a different technology, such as heat pumps, who claim that covers solar PV. It does not. Be cautious if the firm subcontracts installation to a team that holds no certification of its own. The MCS certificate belongs to the company that carries out the work, not the sales company.

• Lapsed certificate: was certified once but the register now shows expired, suspended or withdrawn.
• MCS pending: not a valid status. If they are not certified today, you are not protected today.
• Borrowed certificate number: using another firm's number. Check the register entry matches the company name on your quote.
• Wrong technology: certified for heat pumps or biomass but not for solar PV. MCS is technology-specific.
• Subcontracting to uncertified teams: the firm that physically installs your panels must hold the MCS certificate, not just the sales company.