Almost every guide to choosing a solar installer in the UK tells homeowners to look for MCS certification. The advice is sound, but few of those guides explain what MCS actually is, what the certification covers, and why it matters in financial as well as quality terms. This page sets out exactly what MCS certification means for solar PV installations in Scotland, why it is the gateway to Smart Export Guarantee payments, and what to look for when comparing installers.
What is MCS?
MCS stands for the Microgeneration Certification Scheme. It is the UK national quality assurance scheme for small scale renewable energy products and installation services, including solar PV, solar thermal, heat pumps, biomass heating, and small wind. The scheme was established in 2007 to provide a recognised standard for residential renewable energy installation as the sector grew under the original Feed in Tariff incentives.
MCS is administered by MCS Service Company on behalf of the Department for Energy Security and Net Zero. Two separate forms of certification operate together:
- Product certification: Solar panels, inverters, batteries, and other components are tested and certified to MCS product standards. Only certified products can be used in MCS installations.
- Installer certification: Installation companies are audited and certified to MCS installation standards. Each certified installer is assessed against the MCS installer requirements covering business operations, installation quality, customer protection, and ongoing compliance.
An MCS installation is one carried out by an MCS certified installer using MCS certified products and registered on the MCS installation database at completion. Each registered installation receives an MCS installation certificate which is issued to the homeowner.
Why MCS certification matters financially
The most important practical reason for MCS certification is that it is required to access the Smart Export Guarantee. Under the SEG, electricity suppliers with more than 150,000 domestic customers must offer at least one tariff that pays homeowners for surplus solar electricity exported to the grid. Without an MCS installation certificate, the homeowner cannot register for an SEG tariff and cannot receive export payments.
Over a typical 25 year solar system lifetime, SEG payments are a meaningful income stream. A 4kWp system in Aberdeenshire exporting 800 to 1,500 kWh per year at an average SEG rate of 14.5p delivers cumulative export income of £1,400 to £2,625 over the system’s life. A non MCS installation cannot access any of this. Even a low cost non certified installation that saves £1,000 on the upfront cost typically loses more than that in foregone SEG income over the system’s lifetime, alongside the quality and warranty advantages MCS certified work provides.
For more detail on how SEG income works, see our guide to the Smart Export Guarantee in Scotland.
What MCS covers in installation quality
MCS installer certification is more than a badge. The scheme requires installers to comply with detailed installation standards that govern every stage of the work:
- Survey and design: The installer must carry out a full survey of the proposed installation, assess shading, calculate the expected annual generation using the MCS methodology, and document the system design.
- Component selection: Only MCS certified products may be used in an MCS installation. The product certification covers panels, inverters, mounting systems, and battery storage.
- Installation standards: The MCS 012 standard sets out the technical requirements for solar PV installation, covering structural mounting, electrical safety, fire safety, weatherproofing, and labelling.
- Electrical compliance: Installations must comply with BS 7671, the UK electrical wiring regulations, and the IET Code of Practice for grid connected solar PV systems.
- Documentation: Each installation must produce a complete documentation set including the design specification, generation estimate, MCS installation certificate, Electrical Installation Certificate, and any grid notifications.
- Customer protection: Installers must operate transparent contract terms, provide a 14 day cooling off period, and offer customer protection through an approved consumer code (RECC, HIES, or similar).
The standards are detailed and the audit process for installer certification is rigorous. MCS certified installers go through an annual audit and compliance review by an approved certification body, in addition to ongoing record keeping requirements for every installation.
MCS and consumer code protection
Every MCS certified installer must be a member of an approved consumer protection code. The two main codes for solar PV installers are:
- RECC (Renewable Energy Consumer Code): The most widely used consumer code among MCS solar installers. RECC sets contract standards, advertising rules, deposit protection arrangements, and an independent dispute resolution process.
- HIES (Home Insulation and Energy Systems Contractors Scheme): An alternative consumer code with similar protections, more commonly used by installers operating in both insulation and renewables.
Consumer code membership means homeowners have an independent route to dispute resolution if anything goes wrong with the installation, the contract, or the service. The codes also require deposit protection so homeowners do not lose advance payments if the installer becomes insolvent before completing the work.
An installer that is MCS certified but lacks consumer code membership cannot register installations on the MCS database. The two are linked.
How to verify MCS certification
Before engaging any solar installer, verify their MCS certification directly. The MCS public database is searchable at the MCS website (mcscertified.com). Search for the installer by company name or postcode and check:
- The installer’s MCS certification number is current and active.
- The certification covers solar PV (some installers are certified only for heat pumps or other technologies).
- The installer’s company name and address match the company you are dealing with.
- The installer has no recent suspensions or compliance issues.
Do not rely on logos on a company website or business cards. Verify directly through the MCS database. A few minutes of checking can prevent significant financial and quality problems later.
What is not MCS certified is not eligible for SEG
Some homeowners are tempted by lower quotes from non MCS installers. The cost difference is sometimes 10% to 20%. The trade off is significant and rarely worthwhile.
A non MCS installation:
- Cannot be registered on the MCS database.
- Cannot access Smart Export Guarantee payments.
- May not provide the documentation required by your home insurer or by buyers at the point of property sale.
- Is not subject to MCS quality assurance audit.
- Has no consumer code dispute resolution process.
- May invalidate manufacturer warranties on panels and inverters that require MCS installation as a condition.
The cost of a non MCS installation appears lower at the outset but the lifetime financial position is generally worse, and the protection in the event of any problem is significantly reduced.
MCS and battery storage
Battery storage installed alongside an MCS solar PV system is covered under the same installer certification, provided the battery itself is MCS certified. Most major battery brands (Tesla Powerwall, GivEnergy, SolarEdge) are MCS certified for residential installation in the UK.
A battery added as a retrofit to an existing solar system can also be covered by MCS certification provided the work is carried out by an MCS certified installer. The battery installation does not separately require SEG registration; the SEG tariff applies to the whole solar plus battery installation as registered under the original solar MCS certificate.
What MCS does not cover
It is worth being clear about what MCS does not cover, because the scheme has a defined scope:
- MCS does not cover commercial solar installations above 50kWp. Larger commercial systems are subject to different certification routes.
- MCS does not cover EV chargers. EV charger installation requires OZEV approval (a separate scheme) and an Electrical Installation Certificate from a qualified electrician.
- MCS does not cover roof structural surveys or repairs. If your roof needs structural work before solar can be installed, that work falls outside the MCS installation and is the responsibility of a separate roofing contractor.
Faithful Spark holds NICEIC registration and OZEV approval, covering the certification needs for EV charging and the associated electrical work in a single contractor relationship.
Frequently asked questions
Does MCS certification expire?
The MCS installation certificate issued to the homeowner does not expire. It is a one off document that remains valid for the life of the installation. The installer’s MCS certification, by contrast, is renewed annually through audit and compliance review. Always verify the installer’s current certification status through the MCS database before contracting.
What if my installation was completed but not registered with MCS?
If the installer was MCS certified but did not register the installation, contact the installer first to register it retrospectively. There is a time limit (typically 12 months from installation) for retrospective registration. If the installer is unwilling or unable to register the system, contact MCS directly. If the installer was not MCS certified at the time of installation, the system cannot be retrospectively registered and SEG payments will not be available without re-certification by an MCS installer.
How do I find my MCS certificate number?
Your MCS installation certificate is issued at completion of the installation. The certificate has a unique reference number. If you have lost the certificate, your installer can issue a replacement copy provided the installation is registered on the MCS database.
Can I install solar panels myself and have them MCS certified later?
No. MCS certification covers the installer and the installation process, not just the final result. A self installed system cannot be retrospectively registered with MCS. To access SEG payments, the installation must be carried out from the outset by an MCS certified installer.
Book a free solar survey with a professional installer
Faithful Spark carries out free solar surveys across Aberdeen and Aberdeenshire so you can plan an installation that is registered on the MCS database at commissioning by an MCS certified installer and lets you apply for an SEG tariff with your chosen electricity supplier. See our full guide to solar panel installation in Aberdeen for more on what an MCS certified installation involves.
Faithful Spark Electricians. NICEIC approved. Local Aberdeen team. Serving Aberdeen, Peterhead, Ellon, Fraserburgh and across Aberdeenshire.
