MCS (Microgeneration Certification Scheme)

MCS is a certification scheme for small-scale low-carbon energy technologies. It sets scheme rules and technical standards, while accredited certification bodies assess installers and products within the relevant scope.

For a homeowner, the important distinction is between an MCS-certified installer, an MCS-certified product and the MCS certificate for a completed installation. They are related, but they are not the same thing.

What the scheme covers

MCS includes solar PV, solar thermal, small wind, biomass, heat pumps, micro-CHP and electrical energy storage. Its normal scheme limits are:

• up to 50 kW for electrical technologies such as solar PV and battery storage
• up to 45 kW for a single heat-generating unit
• up to a 70 kW design heat load where multiple heat-generating units form one installation, with no individual unit above 45 kW

These are scope limits in the scheme documents, not market figures. Work outside them may still be lawful and well designed, but it is outside the ordinary MCS scope and needs the appropriate alternative standards and evidence.

Standalone EV chargepoint installation is not one of the listed MCS technologies.

The live scheme transition

As at 22 July 2026, MCS is moving installers from its previous scheme to the redeveloped MCS:2025 installer scheme. The published complaints policy says certification bodies are moving their installer bases across in phases from February 2026 to 31 March 2027.

This matters because an installer may legitimately be certified under either version during the transition. Consumer-protection arrangements, certificate deadlines and document names can depend on the version that applied when the work was carried out.

The scheme version cannot be inferred from a logo. The current MCS register identifies the certified legal entity and its technology scope, while the project records identify the scheme rules and standards applied to the installation.

Under MCS:2025, the main document layers are:

• the Installer Operating Requirements
• the Customer Commitment
• the Installer Agreement
• the relevant technology-specific MCS Installation Standard
• the relevant pre-sale information and system-performance standard
• MCS’s conformity-assessment and supervision rules

The latest versions are held in the MCS Standards and Tools Library. Project records should name the standards or scheme version used rather than simply promising “MCS compliance”.

Installer, product and installation certification

An installer is certified for particular technologies. Certification in solar PV does not, by itself, certify the same business for heat pumps or battery storage. The certified business, contracting legal entity and any umbrella or subcontracting responsibilities are separate parts of the record.

Most product categories used under MCS require active product certification in the MCS Product Directory. MCS:2025 makes an explicit exception for battery storage products because there is no equivalent MCS product-certification requirement for that category. Battery installations still have to meet MIS 3012 and the other applicable product, electrical and fire-safety requirements.

An MCS certificate for the installation is the certified installer’s statement that the completed work meets the applicable scheme requirements. It is not a product warranty, electrical installation certificate, planning approval, building-control certificate or DNO acceptance.

When the certificate should arrive

The deadline depends on the scheme version. Under the MCS:2025 Installer Operating Requirements, the certificate must be raised and provided to the customer no later than 30 calendar days after commissioning.

Some older consumer material refers to a shorter deadline under the previous scheme. During the transition, use the rule attached to the installer’s applicable scheme version rather than mixing the two.

The handover pack should contain the actual MCS certificate as well as the separate commissioning, electrical, DNO, warranty and product records. A promise that the installer will “sort MCS later” is not equivalent to a certificate.

Why MCS can affect grants and export payments

MCS is not a universal legal requirement for installing solar panels, a heat pump or a battery. It becomes commercially important because grants, support schemes and export providers can make certification an eligibility condition.

Two examples show why each scheme must be checked separately:

• The Boiler Upgrade Scheme requires the installer business to hold MCS certification for the relevant technology, and Ofgem checks the MCS installation certificate during voucher redemption.
• For eligible small generation under the SEG (Smart Export Guarantee), Ofgem describes the evidence as an MCS certificate or equivalent. A supplier may set out how it will assess acceptable evidence within the scheme rules.

MCS certification is therefore strong evidence and often the simplest route, but the wording “MCS is required for every export tariff” is too broad. The current rules of the particular grant or tariff control eligibility.

Consumer protection and complaints

Under MCS:2025, installers working under domestic contracts must provide written design and workmanship guarantees and MCS-approved financial protection. MCS also operates a complaints process and requires participation in dispute resolution where its rules apply.

During the transition, the current MCS complaints policy says handling arrangements depend on the scheme version under which the installer was certified when the installation took place, not the date on which the complaint is raised. Consumer Code membership also differs between scheme versions and may still be required by a separate funding scheme even where the redeveloped MCS rules do not mandate it.

If something goes wrong:

1. Put the complaint to the installer in writing and preserve the contract, quotation, survey, performance estimate, certificates and photographs.
2. Check the installer’s certification status and scheme version for the relevant technology and date.
3. Follow the current MCS complaints policy and any applicable Consumer Code or finance-provider process.
4. Keep statutory consumer rights separate from the scheme process; MCS membership does not replace the law.

Installer, product and certificate records

The relevant records include:

• the exact legal entity and technology scope on the MCS installer register
• the current Product Directory entry for products that require MCS certification
• the MCS scheme version and installation-standard edition applied
• responsibility for design, installation, commissioning and certificate registration
• the MCS certificate and underlying handover documents
• separate grant, export-tariff or finance eligibility evidence where applicable

What MCS does not replace

Depending on the technology and site, separate requirements can include:

• planning permission or permitted-development conditions
• Building Regulations compliance and notification
• BS 7671 certification
• G98 or G99 notification or approval
• G100 export-limitation evidence
• product and workmanship warranties
• an export meter, export MPAN and supplier contract
• ongoing servicing and maintenance records

MCS is one important layer in the evidence stack, not a single approval for the whole project.

MCS has operated independently of government since the scheme transferred to the MCS Service Company in 2018. Government and Ofgem can recognise or require MCS within particular policies, but that does not turn MCS itself into a government regulator.

Related entries

• MCS installation standards
• MIS 3002 solar PV standard
• MIS 3005 heat pump standard
• MIS 3012 battery storage standard
• MCS 012 solar mounting standard
• MCS 020 heat pump noise calculation
• SEG
• Boiler Upgrade Scheme