The short answer: MCS certifies that an installer and the products they fit meet set standards. RECC and HIES are consumer codes that protect your money. Without an MCS-certified installation you cannot normally claim export payments or use government-backed funding.
What each one is
| Name | What it is | What it gives you |
|---|---|---|
| MCS | A certification scheme for small-scale renewable installers and products | An MCS certificate for your system, which export tariffs and funding schemes ask for |
| RECC | The Renewable Energy Consumer Code | Rules on selling, deposits, contracts and guarantees, plus dispute resolution |
| HIES | The Home Insulation and Energy Systems consumer code | Similar protections to RECC, including deposit and guarantee protection |
| TrustMark | A government-endorsed quality scheme for work in and around the home | Extra reassurance; required for some funded schemes |
MCS-certified installers must belong to an approved consumer code.
Why MCS matters
- Export payments. The Smart Export Guarantee requires your installation and installer to be certified through MCS or an equivalent scheme.
- Warm Homes loan. The work must be done by an MCS-certified installer.
- Boiler Upgrade Scheme. Heat pump installers must be MCS certified.
- Selling your home. Buyers' solicitors ask for the MCS certificate.
What the consumer codes protect
- Your deposit. RECC limits its members to a deposit of no more than 25% of the contract price, and deposits must be protected.
- Your guarantee. An insurance-backed guarantee covers the workmanship if the installer stops trading.
- How you are sold to. The codes ban pressure selling and misleading claims.
- Disputes. You get access to independent dispute resolution.
How to check an installer
- Search for the company on the MCS website. Do not rely on a logo.
- Check the certificate covers solar PV, not only another technology.
- Check their membership on the RECC or HIES website.
- Ask for their MCS number and confirm it matches the company on your contract.
What you should receive afterwards
- Your MCS certificate
- Confirmation that the network operator has been notified
- A building regulations compliance certificate
- Your insurance-backed guarantee documents
- Product warranties
Equivalent schemes
MCS is the main scheme, but not the only one. Export tariffs also accept schemes accredited as equivalent, such as Flexi-Orb. Check which scheme your chosen funding or tariff accepts.
See how to choose a solar panel installer and how to avoid rogue installers.
Sources
Correct at the time of publication, 14 November 2026.
- MCS: https://mcscertified.com/
- RECC, consumer journey and deposit limits: https://www.recc.org.uk/consumers/customer-journey/
- GOV.UK, Smart Export Guarantee: https://www.gov.uk/government/publications/smart-export-guarantee-seg-earn-money-for-exporting-the-renewable-electricity-you-have-generated
- GOV.UK, Warm Homes Loan Scheme: https://www.gov.uk/warm-homes-loan-scheme
- Ofgem, Boiler Upgrade Scheme: https://www.ofgem.gov.uk/environmental-and-social-schemes/boiler-upgrade-scheme-bus