MCS certification is the single document that turns a solar install into an SEG-eligible, planning-clean, manufacturer-warranty-valid installation. It is also the document most aggressively misrepresented by sales agencies that operate under an "MCS umbrella": one accredited installer at the back, dozens of unaccredited sales agents and subcontractors at the front. This piece walks through verification: the database URL, the certificate-number format, the scope fields to check, the TrustMark interaction, and the named scam pattern that costs SEG eligibility.
Last reviewed: May 2026
TL;DR
- The MCS installer database is at mcscertified.com/find-an-installer and lists every currently certified company by MCS Contractor Number, technology scope and trading status.
- An MCS Installation Certificate is issued per install with a unique MCS Certificate Number; it is not the same as the installer's company-level MCS Contractor Number.
- SEG applications and most manufacturer panel warranties require a valid MCS Installation Certificate dated at or shortly after commissioning.
- TrustMark sits over MCS for consumer protection on home improvement work; many MCS installers are also TrustMark registered but the two schemes are distinct.
- The "MCS umbrella" scam is where an unaccredited sales firm subcontracts the install to a small MCS-certified company; the buyer pays the sales firm, the certificate may issue late or not at all, and SEG eligibility fails.
What MCS actually is
The Microgeneration Certification Scheme (MCS) is the UK scheme that certifies small-scale renewable installations (solar PV, solar thermal, heat pumps, biomass, micro-wind, micro-hydro, battery energy storage systems). It is owned by The MCS Charitable Foundation. The scheme certifies both products (the panels, inverter, battery) and installers (the company that fits the kit). For a solar install to count as MCS-certified, both the products and the installer must be MCS-accredited and an MCS Installation Certificate must be issued. The MCS Installation Certificate is the document SEG suppliers require. Without it the install does not qualify for SEG. Without it most manufacturer panel warranties (the 25-year performance warranty in particular) are voidable. Without it the installation cannot use the permitted-development route under the Town and Country Planning (General Permitted Development) Order in some interpretations because PD relies on the install meeting specified standards.
The mcscertified.com database: how to use it
The primary verification tool is the public installer database at mcscertified.com/find-an-installer. Search by company name or MCS Contractor Number (the company-level number, formatted as MCS NNNNNN). The database shows:
- Company name as registered with MCS (must match the company on the buyer's quote letterhead exactly)
- Companies House number (cross-check on companies-house.gov.uk)
- Technology scope: Solar PV, Battery Energy Storage Systems (BES), Solar Thermal, Air Source Heat Pump, Ground Source Heat Pump, etc.
- Certification status: Live, Suspended, Withdrawn, Expired
- Trading address and contact details
For a solar PV install the scope must include "Solar PV". For a solar plus battery install the scope must include both "Solar PV" AND "Battery Energy Storage Systems". An installer with only Solar PV scope but not BES scope cannot lawfully issue an MCS certificate for the battery component. The catch is that some installers carry only the PV scope and subcontract the battery work, then issue an MCS certificate that only covers the panels.
The MCS Certificate Number format
An MCS Installation Certificate Number is a unique alphanumeric identifier issued at the time of commissioning. The format has been broadly stable since 2018: a prefix of the issuing certification body code, followed by an 8 to 12 digit alphanumeric installation reference. Examples of issuing-body prefixes commonly seen: NAP (NAPIT), HET (HETAS), BRE (BRE Global), MCS-direct certificates have varied prefix conventions.
The certificate document itself is a one-to-two page PDF issued via the certification body's portal, naming:
- The installer's MCS Contractor Number
- The installation address (full postal address)
- Commissioning date
- System size in kWp
- Panel make, model and quantity
- Inverter make and model
- Battery make, model and kWh (if installed)
- Estimated annual generation (SAP calculation)
A "certificate" that arrives as a screenshot, an email signature, a generic letter from the installer, or a document without an MCS Certificate Number is not an MCS Installation Certificate.
How long should the certificate take to issue
The MCS standard is that the installer issues the certificate within 10 working days of commissioning. In practice many issue within a fortnight. If the certificate has not arrived 30 days after commissioning, the buyer should escalate to the installer's certification body (named on the installer's MCS database entry) rather than only to the installer.
Here is where it breaks: SEG suppliers will not open an application without the certificate, and the longer the gap between commissioning and certificate issue, the more grid export passes through unmetered for SEG purposes. The MCS Installations Database (MID) is what suppliers cross-check against; if the install is not on the MID, SEG cannot proceed.
What TrustMark adds and why both matter
TrustMark is the government-endorsed quality scheme for home improvement work, administered by TrustMark Limited. Many MCS-certified installers are also TrustMark-registered. The two schemes overlap but are distinct.
| Scheme | Covers | Required for | Consumer redress |
|---|---|---|---|
| MCS | Technical certification of microgeneration install and installer | SEG eligibility, FIT eligibility (legacy), most manufacturer warranties, some planning interpretations | Through MCS complaints process; via the certification body and via IWA/HIES if subscribed |
| TrustMark | Quality and consumer-protection oversight for home improvement work | ECO4 measures, Boiler Upgrade Scheme installer status, some local-authority retrofit schemes | Through TrustMark complaints process; via insurance-backed guarantee if scheme requires |
For a Boiler Upgrade Scheme (BUS) heat pump install both MCS and TrustMark are mandatory. For a solar PV-only install MCS is mandatory; TrustMark is recommended for consumer-protection coverage but not legally required for SEG.
The "MCS umbrella" scam pattern
The MCS umbrella scam is the most common installer-side abuse of the scheme in the UK as of 2026. The pattern: a large national sales firm with a glossy website does the lead generation, design and customer relationship. The firm itself is NOT MCS-certified. The firm then subcontracts the install to a small MCS-certified local company that issues the MCS Installation Certificate. The customer pays the national sales firm.
The catch is multiple:
- The MCS Installation Certificate is issued to the small subcontractor, not the firm the customer thinks they are buying from. The customer's contract is with the sales firm; the MCS certificate names a different company.
- If the subcontractor goes bust, the workmanship warranty (Insurance-Backed Guarantee via IWA or HIES) may be on the subcontractor's IBG, not the sales firm's, and the IBG may not cover work the sales firm sold.
- The sales firm has no MCS obligation and can fold the trading entity if complaints mount.
On the ground the buyer protection move is: the company named on the quote, the company named on the MCS Installation Certificate, the company on Companies House, and the company on the IBG must all be the same legal entity. If they differ, the certificate may issue but the consumer-protection chain has gaps.
The verification sequence: a working checklist
Before signing anything, a UK buyer should run through this sequence.
- Get the quote on the company's letterhead. Note the full registered company name and any "trading as" line.
- Search the company on mcscertified.com/find-an-installer. Confirm the legal entity is listed, status is Live, and Solar PV (plus BES if a battery is in scope) appears under technologies.
- Cross-check the Companies House number on companies-house.gov.uk. Confirm the company is active and the registered office matches the quote.
- If the quote names a sales-only firm separate from the installing entity, ask in writing which legal entity will issue the MCS Installation Certificate. Get the answer in writing before the deposit.
- Ask for the certification body that issues the company's certificates (NAPIT, HETAS, BRE Global, etc.) and confirm the buyer can escalate to that certification body if the post-commissioning certificate is late.
- Confirm the insurance-backed guarantee provider (IWA, HIES, QANW or similar) and check that the company is on that provider's current member list.
- After commissioning, request the MCS Installation Certificate PDF within 10 working days. Check the certificate number, address, kWp size, panel and inverter details all match the install as delivered.
Devolved nation note: Scotland, Wales, Northern Ireland
The MCS scheme operates UK-wide. The Home Energy Scotland Grant and Loan administered by Energy Saving Trust requires the installer to be MCS-certified. The Boiler Upgrade Scheme (BUS) operating in England and Wales requires both MCS and TrustMark for heat-pump grant eligibility. Wales's Nest scheme uses MCS for any microgeneration measure it funds. Northern Ireland operates outside the GB SEG framework but Power NI's Microgeneration tariff still expects MCS certification on the install.
The catch is that some local-authority retrofit schemes in Scotland and parts of Greater London require additional accreditation (PAS 2030/2035 certification for retrofit coordinators, for example) on top of MCS. A buyer applying through a local-authority route should check the scheme's installer panel rather than only the MCS database.
Suspended, withdrawn and expired: what those statuses mean
An installer's MCS status can change. Live means currently certified. Suspended means temporarily blocked from issuing new certificates, often during a complaint investigation; existing certificates already issued are unaffected. Withdrawn means the certification body has removed the installer for breach of scheme requirements; the company can no longer issue MCS certificates. Expired means the annual renewal lapsed and the installer has not renewed.
A buyer signing with an installer that is currently Suspended is taking on the risk that the install completes but no MCS certificate can issue while suspension stands. A buyer signing with an installer that is Live but later becomes Withdrawn before the certificate issues has a real problem: the certificate may never appear and SEG eligibility may be lost. Check status the day the contract is signed and again on the day before commissioning.
Frequently asked questions
Where do buyers verify an MCS solar installer?
The public database at mcscertified.com/find-an-installer is the only authoritative source. Search by company name or MCS Contractor Number, confirm the legal entity matches the quote, check Solar PV (and BES if a battery is in scope) appears under technologies, and confirm status is Live.
What does an MCS Certificate Number look like?
It is a unique alphanumeric identifier issued by the certification body at commissioning, typically with a body-code prefix (NAP, HET, BRE, etc.) followed by an installation reference. The certificate itself is a one-to-two page PDF naming the installer, the install address, the system size, and the equipment models.
Is MCS the same as TrustMark?
No. MCS certifies microgeneration installers and products. TrustMark is a government-endorsed home improvement consumer-protection scheme. The two often overlap but are distinct registers. Boiler Upgrade Scheme requires both; SEG requires MCS only.
What is the "MCS umbrella" scam?
It is the pattern where a non-MCS-certified sales firm fronts the customer relationship and subcontracts the actual install to a small MCS-certified company. The certificate names the subcontractor; the contract names the sales firm; the consumer-protection chain has gaps. Confirm in writing which legal entity will issue the certificate before paying the deposit.
How long should the MCS Installation Certificate take?
The MCS standard is issue within 10 working days of commissioning. If 30 days have passed without a certificate, escalate to the installer's certification body (NAPIT, HETAS, BRE Global, etc.) and notify the prospective SEG supplier.
Does SEG eligibility require MCS at install time?
Yes. SEG suppliers require a valid MCS Installation Certificate dated at or shortly after commissioning. A retrofit MCS certificate added years after install is not the same and SEG suppliers routinely reject the retrospective route.
