UK Solar and Battery Compliance Calendar 2026-27: Dates and Deadlines
Dates at a Glance
Date | What happens | Who it affects |
|---|---|---|
August 27, 2026 (passed) | Plug-in solar kits up to 800 W become legal to sell and use in Great Britain | Installers advising households |
October 15, 2026 (passed) | The previous edition of BS 7671 is withdrawn, so Amendment 4 applies to all new electrical work | All electrical installers |
November 10, 2026 | MCS 042 battery product standard consultation closes at 11:59 pm | Battery installers and manufacturers |
Coming weeks (no date) | MCS publishes an interpretation note on in-roof solar fire classification | In-roof installers and manufacturers |
Later in 2026 (no date) | Second lender window planned for the Warm Homes Loan Scheme | Installers working with the scheme |
December 31, 2026 to March 17, 2027 | Indicative window for Allocation Round 8 contract signing | Developers of larger solar projects |
March 24, 2027 | Future Homes Standard Requirement L3 takes effect | New-build solar installers |
March 31, 2027 | MCS installer scheme transition deadline, and the last day of 0% VAT on solar and batteries | All MCS installers |
April 1, 2027 | VAT on qualifying installations rises to 5% | Domestic installers and their customers |
September 24, 2027 | Future Homes Standard applies to higher-risk buildings | Developers of tall residential buildings |
From October 2027 (if approved) | Earliest payments under the CMP470 battery queue fee | Battery developers with Gate 2 offers |
What Is Coming First
November 10, 2026: MCS 042. MCS is consulting on a product standard for batteries that would cover safety testing, cybersecurity and declared performance data, including usable capacity. Comments close at 11:59 pm. There is no implementation date, and MCS says installers will get a transition period. See our MCS 042 guide.
Coming weeks: in-roof fire classification. MCS published guidance on November 2 for testing roof-integrated solar systems. It says an interpretation note for certification bodies will follow. See our in-roof fire classification guide.
The Two Deadlines on March 31, 2027
Deadline | What it means | Guide |
|---|---|---|
MCS transition | Every business certified under the existing scheme must have moved to the redeveloped installer scheme | |
0% VAT ends | Qualifying solar and battery installations move to 5%, with the tax point deciding which rate applies to jobs that straddle the date |
The two are unrelated, but they fall in the same quarter. Jobs signed in the new year have less room before the VAT change, and installers still moving to the redeveloped scheme have the same weeks to finish.
New Build and Grid Dates
March 24, 2027: Future Homes Standard. Requirement L3 applies from this date, with September 24, 2027 for higher-risk buildings. A transition rule covers buildings where a building notice, initial notice or full plans application was given before March 24, 2027 and work starts before March 24, 2028. See our Future Homes Standard guide.
Battery queue fee, CMP470. Ofgem has said it is minded to approve a fee of £3,000 to £25,000 per MW on oversubscribed technologies, which in practice means batteries. The consultation closed on October 1, 2026 and no decision date has been given. If approved, the fee is assumed to start in the July 2027 securities statement, with payments from October 2027. See our CMP470 guide.
Allocation Round 8. The official indicative timetable gives December 31, 2026 to March 17, 2027 as the range for contract signing, depending on appeals. See our AR8 guide.
What to Do by When
When | Action |
|---|---|
Before November 10 | Decide whether to respond to the MCS 042 consultation, and ask battery suppliers for their test evidence |
November to December | Check in-roof products' MCS 012 certificates and fire classifications, and watch for the interpretation note |
January to March 2027 | Finish the MCS scheme transition, set quote terms and deposit policy ahead of the VAT change, and confirm new-build specifications against Requirement L3 |
After April 1, 2027 | Quote qualifying installations at 5% VAT and keep completion records for jobs that straddled the date |
Where Design Software Fits
Dates drive scope: a job that must complete before March 31 needs a fixed design early. Design software like Reslink produces the layout, bill of materials and proposal documents from one design, so quotes go out with fixed scope. It does not track regulatory dates or decide compliance.
See the full workflow → Book a demo
Frequently Asked Questions
Q1. What is the next UK solar or battery deadline?
November 10, 2026, when the MCS 042 battery product standard consultation closes.
Q2. When does 0% VAT on solar end?
On March 31, 2027. From April 1, 2027 qualifying installations are charged at 5%.
Q3. When is the MCS installer scheme deadline?
March 31, 2027. Certified businesses must have moved to the redeveloped scheme by then.
Q4. When does the Future Homes Standard solar requirement start?
March 24, 2027, or September 24, 2027 for higher-risk buildings, with a transition rule for projects already in the system.
Q5. Is BS 7671 Amendment 4 in force?
Yes. The previous edition was withdrawn on October 15, 2026, so Amendment 4 now applies to new electrical work.
Q6. Which dates are still unconfirmed?
MCS's interpretation note on in-roof fire classification, Ofgem's decision on CMP470, and the second Warm Homes Loan lender window.
Q7. Are plug-in solar kits legal now?
Yes, kits up to 800 W have been legal to sell and use in Great Britain since August 27, 2026.
Final takeaway
The UK year runs toward two dates: November 10 for the battery product standard and March 31 for the scheme transition and the VAT change. Everything else either has a fixed date later in 2027 or is waiting for a regulator to name one.
You May Also Like
- UK Solar VAT 2027: 0% to 5% and Tax Points for Installers
- MCS 042: UK Battery Product Standard Proposals and Nov 10 Deadline
- BS 7671 Amendment 4: What Solar and Battery EPCs Must Do
Sources
- MCS, Consultations (live consultation listing, November 2026)
- MCS, MCS publishes guidance to address solar PV module fire classification challenges (November 2, 2026)
- House of Commons Library, VAT on solar panels and other energy-saving materials (September 21, 2026)
- Ofgem, Minded-to Consultation: CUSC CMP470, Introducing an Oversubscribed Technologies Commitment Fee (September 17, 2026)
- Department for Energy Security and Net Zero, Plug-in solar: government response (July 2026)
This calendar reflects the sources above and Reslink's UK guides as of November 4, 2026. Dates can change, and the guides carry the detail and sources for each item.
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