Solar Insurance-Backed Guarantee: MCS 6-Year Cover

A solar insurance-backed guarantee (IBG) is the policy that keeps your installer's workmanship promise alive if the installer disappears, and it is about to get much stronger. Under the redeveloped MCS installer scheme, every domestic installation needs an MCS-approved financial protection product giving at least six years of cover, up from a two-year minimum under the current rules. This guide explains what changes, what the cover does and does not do, and what to ask for before you sign.

What is a solar insurance-backed guarantee?

It is insurance that stands behind the installer's warranty. If the company that fitted your panels goes bust, the policy pays for someone else to fix defects covered by the guarantee. Our guide to what happens if your solar installer goes bust walks through the claim route in more detail. The IBG is separate from the manufacturer's panel and inverter warranties, which are covered in solar panel degradation and warranties.

What MCS now requires: six years, £250 excess

MCS says every installer must buy an MCS-approved financial protection product on behalf of their customer. On the redeveloped scheme, the headline terms are:

• At least six years of cover from the moment of installation.
• A capped excess of £250 if you need to claim.
• Remediation of installation problems when you cannot get them fixed by the original installer, including where the installer goes bankrupt, retires, refuses to carry out remedial work, or where the design was at fault.
• Insurer standards: products must be backed by adequate financial reserves and independently audited.

MCS says approved products are already on sale, and installers still on the current scheme can buy them too, which MCS treats as compliant. So you may already be offered the six-year version.

Current rules versus the redeveloped scheme

The comparison above draws on industry guidance from an IBG provider, so treat the current-scheme column as indicative and check the policy wording you are actually given.

When does the six-year rule apply?

All MCS installers must be on the redeveloped scheme by 31 March 2027. Certification bodies are moving businesses across in phases during 2026, so an installer's own transition date may differ, and until they are moved they follow the current rules. That deadline falls on the same day the 0% VAT rate on solar and batteries is due to end; see the solar panel VAT rise in April 2027 if you are weighing when to order.

Does it cover your deposit?

The MCS pages we reviewed do not say. Some providers sell products that bundle deposit cover with the workmanship guarantee, but we could not confirm that deposit protection is a mandatory part of the MCS requirement. Do not assume it. Ask the installer in writing whether your deposit is protected and by whom, and pay any deposit by credit card where possible, as our solar panel scams guide explains.

What the guarantee does not do

• It does not replace the installer's duty to fix faults. You normally go to the installer first; the policy is the safety net when that fails.
• It does not cover everything. Policies have terms, exclusions and claims procedures. Read the schedule, not just the certificate cover page.
• It does not guarantee the equipment. Panel, inverter and battery failures are manufacturer warranty territory.
• Older policies may fall short. Industry guidance says most policies written before 2026 will not meet the 2027 requirements, so an older quote may still show a shorter term.

What to ask your installer before you sign

1. Is the company MCS-certified, and is it on the current or the redeveloped scheme?
2. Which financial protection provider will issue the policy, and for how many years?
3. Is the policy MCS-approved, and what is the excess if I claim?
4. Is my deposit protected, and how?
5. Can I see the policy document and certificate reference before paying anything?

Add these to the checklist in questions to ask a solar installer, and use how to choose a solar installer to compare quotes. For what the certificate itself proves, see the MCS certificate explained.

Bottom line

If you are getting solar quotes now, ask for the six-year MCS-approved financial protection product by name. It costs the installer money, so expect some to be slow to volunteer it, but it is the clearest consumer protection to come out of the MCS redevelopment.