Four updated MCS product standards came into effect on 1 August 2026, and compliance with them became mandatory from that date. Products that have not transitioned to the new versions no longer meet MCS requirements and lose their certification1.
The standards concerned are MCS 005 Issue 4.0 (Solar PV Product Standard), MCS 004 Issue 4.0 (Solar Heating Product Standard), MCS 017 Issue 2.0 (BBIPV Product Standard) and MCS 006 Issue 3.0 (Wind Product Standard)1. The MCS scheme explained page sets out how product certification sits alongside installer certification.
MCS said the update to MCS 005 meant a significant number of solar PV products would no longer be certified from 1 August, which it described as a risk to the wider supply chain, particularly for suppliers and installers holding stock. It has therefore introduced a six-month grace period for MCS 005 products, running from certificate withdrawal on 1 August 2026 until 1 February 20271.
"The purpose of this grace period is to allow existing product stock held within the supply chain to be exhausted and used as part of MCS certified installations. It is not a product certificate extension"
MCS stated that the withdrawal of these products is not due to any identified safety concerns, and that the grace period should not be regarded as an opportunity for manufacturers to continue producing or bringing affected products into the market during it1.
| Item | Detail |
|---|---|
| Standards updated | MCS 005 Issue 4.0, MCS 004 Issue 4.0, MCS 017 Issue 2.0, MCS 006 Issue 3.0 |
| Mandatory compliance from | 1 August 2026 |
| Grace period applies to | MCS 005 (solar PV) products |
| Grace period runs | 1 August 2026 to 1 February 2027 |
| Listing label | 'GRACE PERIOD' after the certification number |
| Certification dates shown | 01/08/2026 to 01/02/2027 |
Why it matters for households
MCS certification is the route by which a product or installation can qualify for government-backed incentives, so a certificate that lapses changes what a household can claim for. For solar PV, the practical effect is that panels and related products already in the supply chain remain usable in MCS certified installations until 1 February 2027, even though their certificates were withdrawn on 1 August 20261. A household offered such a product is therefore looking at equipment that is no longer certified in its own right but is permitted for a defined window.
The distinction MCS draws matters: the grace period covers stock already in the chain, not new production or new imports of affected products1. It is not an extension of the product certificate. The manufacturer certification and approvals page explains how product listing works, and product markings and standards covers the marking regimes that sit around it. For homes using solar heating, wind or building-integrated PV products, no grace period has been reported; the updated standards applied from 1 August 20261.
What happens next
Duplicate listings of products in the grace period are marked in the MCS Installations Database and the MCS Product Directory with the label 'GRACE PERIOD' after the certification number, with certification dates displayed as 01/08/2026 to 01/02/20271. MCS certified installers may use grace period products in MCS certified installations until 1 February 2027, and MCS stated the grace period will not be extended1. MCS said it will continue to work with manufacturers and product certification bodies to minimise disruption before the deadline, and will provide updates and reminders. Questions go to the MCS Helpdesk on 0333 103 8130 or hello@mcscertified.com1.