The Department for Energy Security and Net Zero published a consultation on 12 October 2026 that proposes keeping air-to-air heat pumps outside the Clean Heat Market Mechanism. It also asks for views on targets for years 3 to 6 of the scheme and on extending the regulations until 2032. It closes at 11:59pm on 8 November 2026, so there are about four weeks to respond.
If you are weighing an air-to-air system for your home or business, this will not stop you buying or installing one. It does shape where the heat pump industry is being pushed, and the department is openly asking for evidence on air-to-air, which makes it a rare chance for installers to be heard.
What the Clean Heat Market Mechanism is
The Clean Heat Market Mechanism, or CHMM, is a manufacturer obligation, not a consumer grant. GOV.UK's guidance says it "places an obligation on manufacturers supplying gas and oil boilers in the UK market". Those firms have to meet heat pump installation targets in proportion to their fossil fuel boiler sales, by supplying heat pumps themselves or buying credits from others. Heat pump makers that are not obligated earn credits instead.
The consultation document says the scheme came into force on 1 April 2025. Year 1 (2025/26) set a target of 6% of eligible boiler sales, and year 2 (2026/27) is 8%.
What is being proposed
The consultation page says it seeks views on "the targets for years 3 to 6 of the scheme". The proposed levels in the document are:
- Year 3 (2027/28): 9% of relevant sales
- Year 4: 12%
- Year 5: 15%
- Year 6 (2030/31): 18%
The scheme regulations currently run from 1 April 2025 to 31 March 2029, and the government intends to extend that to 31 March 2032. It also proposes that heat pump installations in new build homes should generate credits from 2027/28, provided they are MCS-certified. For how new builds are changing, see our piece on the Future Homes Standard. Other mechanics, including the £500 payment in lieu, would continue.
Why the air-to-air exclusion matters
The page lists "continuing the exclusion of air-to-air heat pumps, heat batteries and heat interface units". Today only domestic-scale hydronic heat pumps, meaning air-to-water or ground-to-water, count as qualifying installations. The document says about 89% of existing UK homes have hydronic central heating, and that the scheme should stay focused on that market.
It gives reasons for leaving air-to-air out: such systems are expected to represent only a modest share of heating system replacements, and UK manufacturing of them is very limited. It also says the government "would welcome any evidence to the contrary".
The practical meaning, in our reading, is that an air-to-air installation does not earn a credit, so obligated manufacturers have no scheme-driven reason to promote it. That is not the same as a ban or a grant decision, and it does not change the product you can buy.
Do not confuse it with the Boiler Upgrade Scheme
The Boiler Upgrade Scheme (BUS) is a separate scheme, and it pays grants to households rather than setting targets for manufacturers. It does cover air-to-air: the GOV.UK Boiler Upgrade Scheme page lists "£2,500 towards an air-to-air heat pump" among the grants available. So an air-to-air system can attract a grant while still sitting outside the CHMM. Our guide to air-to-air heat pump grants covers who qualifies and how to apply.
How to respond
- Read the 17-page consultation document.
- Respond online using the link on the consultation page, which DESNZ calls its preferred method, or email [email protected].
- Say whether you respond as an individual or for an organisation, and answer the numbered questions. Questions 14 to 16 cover air-to-air heat pumps, including evidence on the role they will play in new build and retrofit homes.
- Get it in before 11:59pm on Sunday 8 November 2026.
The department says it will publish a summary of responses on GOV.UK. If you install or specify air-to-air systems, real examples of how they are used for heating are the sort of evidence it is asking for.
