What is the Clean Heat Market Mechanism (CHMM)?
The Clean Heat Market Mechanism (CHMM) is a UK government scheme that requires manufacturers of fossil-fuel boilers and heating appliances to sell a proportion of heat pumps (or buy heat pump credits) each year. The aim is to grow the heat pump market and cut carbon from heating.
Year 1 of the CHMM began in April 2025 with a lower target; Year 2 starts in April 2026 with the obligation stepping up to an 8% heat pump target. That means more heat pumps in the supply chain, more demand for installations, and more pressure on installers to deliver MCS-compliant jobs with the right evidence.
CHMM Year 2: The 8% Target
From April 2026, the CHMM Year 2 target means manufacturers must meet an 8% heat pump sales ratio (or equivalent in credits). In practice:
- More heat pump units will be pushed into the market
- Boiler Upgrade Scheme (BUS) demand is already high; CHMM adds structural demand from the supply side
- Installers who can turn quotes into completed, MCS-signed-off installations will be in the strongest position
For installers, the message is clear: demand for heat pump installations will remain strong. The bottleneck is often survey capacity and evidence quality—getting the right ASHP survey and heat loss calculation in place early so projects don't stall at MCS or BUS evidence checks.
MCS:2025 and Evidence Requirements
MCS:2025 (the latest MCS standards suite) places a strong emphasis on documented evidence: heat loss reports, system design, site photos, and compliance with standards such as MCS 020 (noise) and MCS 021 (heat pump installation). Installers who rely on ad-hoc site visits or incomplete paperwork risk delays, callbacks, and failed grant applications.
Professional survey outputs give you:
- Heat loss calculations for correct heat pump sizing (required for MCS and BUS)
- ASHP site assessments with measurements, photos, and feasibility notes
- Evidence packs that support MCS certification and BUS applications from day one
With CHMM Year 2 increasing the flow of heat pump work, having a reliable survey partner reduces risk and helps you scale without getting stuck in compliance back-and-forth.
What Installers Should Do Now
Before April 2026 and through CHMM Year 2:
- Lock in survey workflows: Use consistent ASHP surveys and heat loss deliverables so every job has the evidence MCS and BUS require.
- Plan for volume: CHMM and BUS together mean more enquiries; make sure you can turn them into completed installations, not lost leads.
- Stay on top of MCS:2025: Keep an eye on MCS updates and ensure your evidence (noise, heat loss, design) matches the latest requirements.
If you're an installer and want to discuss survey scope, lead times, or evidence packs for CHMM and BUS work, we're happy to talk through your pipeline—get in touch to confirm scope, evidence requirements, and lead time before you book.
Conclusion
CHMM Year 2 (April 2026) and the 8% heat pump target reinforce the direction of travel: more heat pumps, more demand for compliant installations, and more need for professional survey evidence. Installers who invest in robust ASHP and heat loss survey workflows now will be better placed to win and deliver work as the mechanism ramps up.