Solar & Heat Pump Certifications: Solar Keymark, SRCC, MCS Explained

Why do heating products need certification at all?

Certification turns a manufacturer's performance claim into verified, comparable data — and in renewable heating it is also the key that unlocks public money. Across Europe and North America, subsidy schemes fund only products tested by accredited laboratories and listed in official certification databases, which makes the certificate as commercially important as the product itself.

The system has two layers. Standards — ISO and EN documents — define how to test: ISO 9806 for solar collectors, EN 14511 and EN 14825 for heat pumps, EN 12897 for storage water heaters. Certification schemes sit on top and answer who verified it: an accredited laboratory runs the standard test, a certification body audits the factory, and the results enter a public database that regulators and subsidy administrators trust.

What does Solar Keymark certify — and why do subsidy schemes require it?

Solar Keymark is the CEN/CENELEC certification mark for solar thermal products: collectors tested to EN 12975 and EN ISO 9806, factory-made systems to EN 12976 and custom-built systems to EN 12977. Certificates are valid for five years, factory production is inspected annually, and every certificate's performance datasheet — optical efficiency, heat loss coefficients, annual output — is publicly searchable in the Solar Keymark database.

That transparency is exactly why funding bodies lean on it. Public subsidy schemes need verified performance rather than brochure figures, so Solar Keymark has become the de facto prerequisite across Europe: Germany's BEG/BAFA collector lists, Italy's Conto Termico and numerous regional programmes accept it as standard evidence. The practical installer rule remains: no Keymark, no subsidy, in most of the EU.

PVT products are certifiable too. A PVT hybrid collector runs the same ISO 9806 thermal tests as any collector, with its electrical side covered by the usual IEC photovoltaic standards — which is how hybrid panels qualify for solar thermal subsidy lists alongside conventional collectors.

What are SRCC OG-100 and OG-300 — and which one do you need?

OG-100 certifies the solar collector; OG-300 certifies the complete residential solar water heating system — and North American market access usually runs through one of the two. Both ICC-SRCC programmes are referenced in the IBC, IRC, IMC and IPC model building codes, in California's Title 24 energy code and in ENERGY STAR criteria (the federal residential tax credit, which also required SRCC certification, ended for systems placed in service after 31 December 2025), so an uncertified product is effectively locked out of code approval and incentive money alike.

The choice follows what you sell. A collector manufacturer supplying system integrators needs OG-100. A company selling packaged residential systems needs OG-300, which adds location-specific annual energy ratings calculated for roughly 200 North American sites — the US counterpart to the site-referenced annual output figures on European Keymark datasheets. Because OG-100 accepts ISO 9806 test data, a European or Turkish manufacturer can typically extend its existing Keymark laboratory results toward SRCC certification rather than starting the test programme from zero.

What is MCS — and why is it mandatory for UK grants?

MCS (Microgeneration Certification Scheme) is the United Kingdom's certification for small-scale renewables, and it is unusual in certifying two things at once: the product and the installer. Both sides must be certified for a homeowner to receive support under the Boiler Upgrade Scheme — and the 2026 BUS guidance makes MCS the sole accepted certification route.

The scheme is also mid-way through its biggest redesign in a decade: a redeveloped installer scheme rolls out through 2025–2026, introducing a Technical Supervisor role responsible for technical competence inside each certified business. For manufacturers exporting to the UK the message is clear — product listing alone is not enough; the installer network must hold MCS certification too, or the end customer loses the grant. For homeowners, the checklist is equally short: verify both the installer's MCS number and the product listing before signing anything.

How is a heat pump certified? Heat Pump Keymark vs the EHPA Quality Label

Heat pumps carry their own CEN certification: the Heat Pump Keymark, which marked its tenth anniversary in 2026 and builds on EN 14511 and EN 14825 for heating performance, EN 16147 for domestic hot water heat pumps and EN 15879 for direct-exchange ground-coupled units. Alongside it stands the EHPA Quality Label, the industry association's scheme; the two are complementary rather than competing, and Heat Pump Keymark test data commonly feeds the eligibility lists behind national subsidy programmes.

Certified seasonal performance matters more every year as the market scales. European heat pump sales grew 13% in 2025 to 2.88 million units (EHPA), and subsidy schemes from Germany's BEG to the UK's BUS set their funding thresholds in certified seasonal efficiency, not manufacturer claims — a heat pump without recognised certification is invisible to the funding system regardless of how well it performs.

Which standards govern hot water storage tanks?

Storage tanks answer to their own family of standards, centred on pressure safety, heat loss and corrosion protection rather than energy conversion.

DIN 4753 answers the question every cylinder owner eventually asks — why enamelled tanks carry a magnesium anode that must be inspected every couple of years: its parts 3 and 6 treat enamel and cathodic protection as one combined corrosion defence, not two options. The full engineering story of tank types, sizing and materials is in the storage tank guide.

How does one laboratory test open many markets?

ISO 9806 is the single global test standard for solar collectors, and that is the quiet efficiency of the whole certification system: one accredited test campaign generates the data behind Solar Keymark in Europe, SRCC OG-100 in North America and TSE certification in Türkiye — one test, many markets. For specifiers it means certified datasheets from different schemes describe the same physics and can be compared with confidence; for manufacturers it means multi-market certification without repeating the full laboratory programme for every region.

Solimpeks runs exactly this playbook from its Konya factory: Wunder flat-plate collectors carry Solar Keymark certificates issued by DIN CERTCO, with ICC-SRCC OG-100 certification for the ALS range and a TSE product certificate, while the PV-T hybrid panels hold a Solar Keymark licence from Kiwa Cermet Italia — with the factory surveillance each scheme requires. For a buyer in any of the 96+ countries Solimpeks exports to, the verification path is always the same: look the certificate up in the scheme's public database and read the tested numbers, not the brochure.