MCS certification: what it means and why it matters

Certification comes up in every solar sales conversation and is usually explained badly, either as a meaningless formality or as a guarantee of quality. It is neither.

Understanding precisely what it covers matters, because one of the things it unlocks is the ability to be paid for the electricity you export, and that is worth a quantifiable amount of money every year for as long as you own the system.

What it is

The Microgeneration Certification Scheme is a standards framework for small scale renewable installations: solar photovoltaics, battery storage, heat pumps, wind and other technologies, each certified separately. It certifies two different things:

Products. Panels, inverters and other equipment meeting defined standards.

Installers. Businesses assessed against a defined standard for how they survey, install, commission and document work, and reassessed periodically. For solar that standard includes producing the generation estimate by the scheme’s method, postcode irradiance, orientation, pitch and a shading assessment, which is why “which tool produced this estimate” is such a revealing question.

A certified installation is one where certified products were fitted by a certified business, and registered on completion.

Why it matters commercially

The practical consequence is export payments.

Electricity suppliers offering export tariffs need a way to establish that an installation is genuine, is what it claims to be, and was competently done. Certification is what they rely on: Ofgem’s Smart Export Guarantee eligibility requires MCS or equivalent certification, and suppliers check the certificate when you register.

Put a number on what that gates. A household exporting 2,000 kilowatt hours a year on a 12p tariff collects £240 a year. An uncertified installation may generate identically and still forfeit that, every year, indefinitely, because no supplier will register it. Over a system’s life the certification gap is thousands of pounds, which is why the cheapest quote in a pile, if it comes from an uncertified outfit, is frequently the most expensive thing on the table.

It also commonly matters for grant schemes, which usually require certified installation as a condition of funding.

What it does not guarantee

This is where expectations go wrong.

It is not a workmanship guarantee for your specific job. It certifies that the business meets a standard and is subject to assessment. It does not inspect every installation.

It is not a warranty. Warranties come from manufacturers and from the installer, separately, and need reading as three distinct documents.

It is not a promise the company will still exist. Certification does not underwrite the installer’s future solvency, though the associated consumer protections cover some of what happens if they fail.

It does not vouch for the sales process. A certified installer can still give you an optimistic generation estimate, an unstated self consumption assumption, and a projection inflated by compounded energy price rises. The certificate constrains the installation, not the brochure.

So: treat certification as necessary rather than sufficient. It filters out some risk; it does not select a good installer for you.

Checking a registration

Do this rather than accepting a logo:

1. Go to the scheme’s own register, not a link from the installer’s site.
2. Search by company name or registration number.
3. Confirm the business is currently certified, and certified for the specific technology you are buying.

That last point matters. Certification is per technology. A business certified for solar photovoltaics is not automatically certified for battery storage or heat pumps, and the paperwork you need depends on what is being installed. A package quote spanning panels and a battery needs the registration to cover both.

The certificate itself

On completion you should receive a certificate recording the installation, its components and its estimated performance. Keep it. You will need it when applying for an export tariff, it is part of what the network operator notification process expects to exist, and it forms part of the documentation for a future sale of the property, where a buyer’s conveyancer may ask for it.

If a certificate has not arrived within a reasonable period after commissioning, chase it. This is the item most likely to be overlooked and the one you most need, and an installer’s speed at producing it is a last, late signal of how they run their paperwork generally.

Consumer protection

Certified installers must belong to a consumer code, which covers the sales process, contract terms, deposit protection and complaint handling. RECC is the largest for this sector.

Deposit protection is the part worth understanding before you pay anything. Ask specifically what protection applies to your deposit and under which code, and confirm the answer independently on the code’s own site rather than taking it from the salesperson. The size and timing of payments is part of the price, and protection is what makes a normal deposit acceptable.

Where it sits in choosing an installer

Certification is a filter, not a decision. Having filtered, judge on:

• Whether they surveyed the roof properly, including shading.
• Whether the generation estimate is defensible and the tool is named.
• Whether the exclusions are stated up front.
• Whether the specification matches your roof rather than a template, which is what most of the gap between two honest quotes turns out to be.

Those are the things that determine whether the installation performs like the projection, and none of them are what certification measures. Then check the projection itself against your own model with your own numbers, which no certificate can do for you.