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MCS certification and why it matters

What MCS is, what an MCS installer must give you, the 2026 changes (MCS:2025, consumer codes now voluntary) and how to complain.

Checked 9 October 2026 · Sources

Installer in a hard hat and hi-vis vest fixing solar panels on a barn roof
Solar panels being fitted on a barn roof near Balcombe, West Sussex · Photo: Kristian Buus / 1010 Climate Action, CC BY 2.0

What MCS is

MCS (the Microgeneration Certification Scheme) is the UK's quality mark for small-scale renewable energy. It certifies both products and installers.

When an MCS installer finishes your system, it registers the job on the MCS database, which produces an MCS certificate. That certificate matters:

  • you need it (or an equivalent) to be paid under the Smart Export Guarantee
  • the government's Warm Homes Loan Scheme requires an MCS-certified installer and product
  • MCS says many insurers require MCS for renewable technologies
  • an installation can't be certified afterwards — it has to be done by an MCS installer at the time

What an MCS installer must give you

  • A written estimate before you sign of how much electricity the system will make in a year (worked out as kWp × Kk × shade factor) and how much of it you'll use yourself, with a warning that the figures aren't guaranteed.
  • A clear quote. MCS guidance (February 2026) says quotes should include the installer's MCS number, an itemised list of products by make and model, prices with and without VAT, a timeline, the deposit and how it's protected, guarantees and warranties with their length, any financial protection, and how long the quote is valid.
  • A written contract covering who gets any permissions, your cancellation rights, the complaints procedure (including escalating to MCS), dispute resolution and after-sales service.

Changes in 2026: MCS:2025 and consumer codes

MCS has redeveloped its installer scheme, known as MCS:2025. Installers are moving to it in phases between February 2026 and 31 March 2027.

Under the old scheme, MCS installers had to belong to a consumer code — the Renewable Energy Consumer Code (RECC) or HIES. Under MCS:2025, consumer-code membership is no longer mandatory, though installers can stay members voluntarily. So for now, some MCS installers are RECC or HIES members and some aren't. Our directory shows membership as each installer states it, and as verified where we've checked.

If something goes wrong

Under MCS's complaints policy (February 2026):

  1. Complain to the installer first. MCS treats 14 days as a reasonable maximum for a response.
  2. If that doesn't resolve it, escalate to MCS.
  3. MCS can refer eligible disputes to its dispute resolution partner, the Furniture & Home Improvement Ombudsman. This is free for you, and the outcome is binding on installers certified to the new scheme. It applies to contracts made on or after 1 January 2025; for older contracts, go through the installer's consumer code.

Complaints about finance can go to the Financial Ombudsman Service. Ask your installer about any insurance-backed guarantee or other financial protection.

Check an installer

Search the installer on the MCS installer search, or use our directory's MCS verified filter to see installers whose MCS certification we've checked. Find MCS-certified installers.

Sources

  1. MCS: Information for consumers
  2. MCS: MIS 3002 The Solar PV Standard (Installation) issue 5.0
  3. MCS: Guidance for Contracts and Quotations (2026)
  4. MCS: Complaints Policy (2026)
  5. MCS: Becoming certified
  6. DESNZ: Warm Homes Loan Scheme – scheme rules (Sept 2026)
  7. Ofgem: SEG guidance for generators
  8. MCS: Find an installer

This guide is general information, not financial or legal advice. Rules and prices change, and some differ between England, Wales, Scotland and Northern Ireland — check the sources for your situation.