MCS (Microgeneration Certification Scheme) is the UK's quality-assurance scheme for small-scale renewables, certifying both products and installers of heat pumps, solar thermal, and solar PV up to 45 kW thermal or 50 kW electrical. It is the gateway to UK funding: the Boiler Upgrade Scheme grant — £7,500 toward an air or ground source heat pump — is paid only for MCS-certified installations.
What does MCS actually certify?
MCS certifies two distinct things, and a compliant installation needs both. Product certification confirms that a heat pump, solar collector or PV module meets the scheme's technical standards, verified through accredited laboratory testing. Installer certification confirms that a company designs and installs to the MCS installation standards, holds the required competences, and belongs to a consumer protection scheme — assessed initially and then through ongoing surveillance.
The scheme covers microgeneration up to 45 kW thermal and 50 kW electrical, which spans essentially all domestic and small commercial systems in the UK. An installation only counts as MCS-certified when a certified installer fits a certified product and registers the job on the MCS database, generating the certificate that grant schemes ask to see.
Why does MCS decide whether you get a grant?
Because UK support schemes outsource their quality control to it. The Boiler Upgrade Scheme — worth £7,500 toward an air or ground source heat pump in 2026 (£9,000 for off-gas-grid homes heated by oil or LPG until March 2027) — is payable only for installations carried out by MCS-certified installers using MCS-certified products; the installer applies for the voucher on the householder's behalf, so without an MCS installer there is no route into the scheme at all. The same gate has applied to earlier UK schemes since MCS was created in the late 2000s, which is why the register of certified installers is effectively the UK's approved-installer list for renewables.
| Element | Who holds it | What it proves | Checked by |
|---|---|---|---|
| Product certificate | Manufacturer | Product meets MCS standards | Accredited certification body |
| Installer certificate | Installation company | Competent design and installation | Certification body audits |
| Installation certificate | The individual job | Certified product + certified installer | MCS database registration |
What should an MCS heat pump installation include?
A room-by-room heat load calculation is the foundation — MCS installation standards require sizing from calculated losses, not rules of thumb — followed by emitter checks, cylinder specification, an annual performance estimate and a documented handover pack. The customer must also get consumer-code protection covering deposits and workmanship disputes.
That paper trail is precisely what separates a compliant installation from a guess, and it gives homeowners a checklist for vetting quotes: the questions to ask are laid out in How do you choose a good heat pump installer? and the design red flags in How do I judge a heat pump installation?.
How does MCS relate to Solar Keymark and Heat Pump Keymark?
They answer different questions for different markets. Solar Keymark and Heat Pump Keymark are European product certification schemes proving tested performance across the EU; MCS is a UK scheme certifying products and installers for the UK market. The underlying test methods overlap heavily — solar collectors are tested to ISO 9806 under both regimes — so manufacturers serving both markets certify against each scheme from the same engineering base. Solimpeks' collectors carry Solar Keymark and SRCC certification, the European and North American counterparts of this product-level proof.
For a UK buyer the practical rule: check the installer on the MCS register before signing, and check the exact product model is MCS-listed — certification attaches to specific models, not brands. Certification costs are modest per job and, given the grant amounts they unlock, pay for themselves many times over; see how much certification adds to installation cost.
Frequently asked questions
Is MCS certification a legal requirement in the UK?
No — you may legally install a heat pump or solar system without MCS. But grant funding, including the £7,500 Boiler Upgrade Scheme, requires it, and many lenders, insurers and export-tariff schemes ask for the MCS certificate too, so non-MCS installations sacrifice real money.
How do I check whether an installer is MCS certified?
Search the public register on the MCS website by company name or postcode. Verify the company is certified for the specific technology — heat pumps, solar thermal or PV — since certification is held per technology, not as a blanket approval.
Does MCS cover solar thermal as well as heat pumps?
Yes. MCS covers heat pumps, solar thermal, solar PV, biomass and other microgeneration technologies up to 45 kW thermal or 50 kW electrical, each with its own product and installation standards.
Who applies for the Boiler Upgrade Scheme grant — me or the installer?
The MCS-certified installer applies for the voucher on your behalf and deducts the grant from your invoice. This is why an MCS installer is unavoidable: the application route runs through them, not the householder.