Solar · Advice
What do I lose if my solar installer is not MCS certified?
Short answer
Most money. Without an MCS certificate (or equivalent such as Flexi-Orb), suppliers need not pay you under the Smart Export Guarantee, and you cannot use the Warm Homes Loan Scheme, Warm Homes: Local Grant or ECO4. The 0% VAT relief does not depend on MCS, and building regulations still apply.
Last checked 24 September 2026 · 1 source
In more detail
- WHLS: MCS product + MCS installer
- WH:LG: products on MCS Product Directory; battery installer MCS to MIS 3012
- ECO4: MCS or alternative scheme installer
- HES (PV-T): MCS installer and MCS/Solar Keymark product
The facts, dated
- 01WHLS requires MCS certified product installed by MCS certified installer
scheme · UK · checked 24 September 2026 · GOV.UK
Sources
Last checked: 24 September 2026