What MCS actually is
MCS stands for Microgeneration Certification Scheme. It is the UK government-backed quality standard for small-scale renewable energy installations. When an installer is MCS-certified, it means they have been independently assessed against a set of technical standards covering system design, installation quality, and consumer protection.
The scheme is run by MCS (formerly known as the Microgeneration Certification Scheme) and administered through certification bodies like IAA, NAPIT, and NICEIC. These bodies audit installers annually and can withdraw certification if standards slip.
Why it matters for you as a homeowner
There are three practical reasons to choose an MCS-certified installer.
- Smart Export Guarantee. The SEG pays you for surplus electricity you export to the grid. Energy suppliers are only required to accept applications from homeowners whose systems were installed by an MCS-certified company. No MCS, no export payments.
- Green mortgage incentives. Lenders including Nationwide, Barclays, and Halifax offer cashback or reduced rates for energy-efficient home improvements. Most require the installation to be MCS-certified. Nationwide's Green Reward, for example, requires an MCS certificate and invoices to be submitted within three months of installation.
- Consumer protection. MCS-certified installations come with a guarantee backed by the installer's certification body. If the company goes bust, you still have a route to resolve warranty claims through the certification body's guarantee scheme. With an uncertified installer, your recourse is limited to standard consumer law.
What MCS certification requires from an installer
To gain and keep MCS certification, an installer must meet specific requirements.
- Employ qualified designers and installers with relevant electrical and roofing competencies.
- Design every system to MCS technical standard MIS 3002, which covers panel sizing, orientation assessment, shading analysis, and predicted energy output.
- Carry appropriate insurance including public liability and professional indemnity.
- Submit to annual audits by their certification body, including inspections of completed installations.
- Maintain a complaints procedure and participate in their certification body's dispute resolution scheme.
How to check if an installer is MCS-certified
Go to mcscertified.com and use the "Find an Installer" search. Enter the company name or your postcode. The database shows every currently certified installer, their certification body, and which technologies they are certified to install. If a company is not in this database, they are not MCS-certified, no matter what their website claims.
Some companies describe themselves as "MCS-standard" or "working to MCS standards" without holding the certification. These phrases have no official meaning. Either a company is MCS-certified or it is not.
What happens if your installer is not MCS-certified
You can still have solar panels installed by a non-MCS installer. It is not illegal. But you lose access to the SEG, most green mortgage incentives, and the certification body's guarantee scheme. You also have no assurance that the system was designed to the technical standards that MCS requires. For most homeowners, the financial benefits of MCS certification outweigh any saving from choosing an uncertified installer.
