The Department for Energy Security and Net Zero (DESNZ) has confirmed that from 2026/27 onwards, the Microgeneration Certification Scheme (MCS) will become the sole certification route for installations under its major clean-heat programmes. These include the Boiler Upgrade Scheme (BUS), Energy Company Obligation 4 (ECO4), Warm Homes: Social Housing Fund (WH-SHF), Warm Homes: Local Grant (WH-LG), and the Clean Heat Market Mechanism (CHMM).

In its published response to two consultations, DESNZ announced that it will remove the option for alternative certification schemes or equivalence routes across these programmes. It also confirmed that under the CHMM, the Year 2 (2026–27) target level will be set at 8% of relevant boiler sales.

According to DESNZ, the move is intended to streamline certification processes, enhance consumer protection, and provide greater clarity for industry participants about the required standards for clean-heat installations. The department noted that this decision aligns with its broader decarbonisation strategy and the forthcoming Warm Homes Plan.

In response, MCS released a statement saying: 

MCS looks forward to continuing our work with the Department for Energy Security and Net Zero in supporting the deployment of clean heat measures across the UK under government schemes. As a charity-owned company, we are focused solely on improving quality and consumer protection for the greater good of the sector. The effective delivery of the Scheme is our single focus; to give everyone confidence in home-grown energy.  

We have been defining, maintaining and improving quality in the sector for almost two decades, and in that time there have been more than 2.2 million MCS certified installations by close to 6,000 certified installers.  As the renewables sector has grown, so too has MCS. We have invested in growing our skilled and dedicated Customer Experience and Technical Assessment teams, ensuring we can continue to drive high standards and strong consumer protections at scale.  

Of course, supporting the delivery of government funded schemes is only one part of the work MCS does – our certification of quality goes far beyond this, working to give everyone in the UK confidence in home-grown energy. MCS’s product certification Scheme also certifies products against MCS Standards, ensuring installations are high-quality, efficient, and safe, including those paid for by householders themselves and going into new builds.