The Clean Heat Market Mechanism (Amendment) Regulations 2025

Published: Thu 20th Nov 25

These Regulations amend the Clean Heat Market Mechanism (CHMM) Regulations 2025, which established the mandatory scheme requiring boiler manufacturers to meet escalating targets for installing low-carbon heat pumps proportionate to their fossil fuel boiler sales in the UK. The amendments officially designate the Microgeneration Certification Scheme (MCS) as the sole approval scheme for CHMM compliance, update the criteria for what qualifies as a hybrid heating system, and most significantly, increase the required low-carbon heat installation target for scheme years beginning April 1, 2026, from 6% to 8% of relevant boiler sales.

Arguments For

Addresses market uncertainty by confirming the Microgeneration Certification Scheme (MCS) as the sole approved certification body for the CHMM, providing clarity for industry participants.
Adjusts the definition of hybrid heating systems to better align with practical installation scenarios, ensuring systems are only judged on necessary functions like water heating.
Raises the immediate low-carbon heat installation target from 6% to 8% for scheme years starting April 2026, accelerating industry shift towards heat pumps and meeting greater decarbonization goals.
Provides the Secretary of State ongoing flexibility to approve future versions of the MCS, ensuring the certification standard remains current and technically robust.

Arguments Against

Increasing the low-carbon heat target to 8% so quickly may impose significant compliance burdens or supply chain constraints on manufacturers if sufficient installer capacity or product availability is not present.
Centralizing approval authority for the certification scheme solely with the Secretary of State could be seen as reducing industry input in standard-setting processes beyond the initial establishment phase of the MCS.
The amendments, particularly concerning commencement dates (some in December 2025, one section in April 2026), introduce potential complexity for immediate operational planning by manufacturers.

The Secretary of State makes these Regulations in exercise of the powers conferred by sections 143, 144, 145 and 331(2) of the Energy Act 2023. In accordance with section 151(4) of that Act, the Secretary of State has given notice to, and considered the representations of, the Scottish Ministers, the Welsh Ministers and the Department for the Economy in Northern Ireland.

The Secretary of State created these Regulations using powers granted by specific sections of the Energy Act 2023.

Before enacting them, the Secretary of State notified the devolved governments in Scotland, Wales, and Northern Ireland and took their feedback into account, as required by section 151(4) of that Act.

Citation1.

These Regulations may be cited as the Clean Heat Market Mechanism (Amendment) Regulations 2025.

This citation section establishes the formal name for this piece of legislation as the Clean Heat Market Mechanism (Amendment) Regulations 2025.

Commencement2.

(1)

These Regulations come into force on 12th December 2025, subject as follows.

(2)

Regulation 8 comes into force on 1st April 2026.

This specifies when the amendments take effect.

Sub-article (1) states that the majority of these Regulations become law on December 12, 2025.

However, sub-article (2) creates an exception, delaying the start date for Regulation 8 until April 1, 2026.

Extent3.

These Regulations extend to England and Wales, Scotland and Northern Ireland.

This section defines the geographical application of the Regulations, confirming they apply across England, Wales, Scotland, and Northern Ireland.

Amendments to the Clean Heat Market Mechanism Regulations 20254.

The Clean Heat Market Mechanism Regulations 2025 are amended in accordance with the following provisions.

This merely introduces the following provisions by stating that the primary Clean Heat Market Mechanism Regulations 2025 are being modified according to the rules laid out subsequently.

Regulation 2 amended (interpretation)5.

In regulation 2(1), for the definition of “certification scheme”, substitute—

““certification scheme” has the meaning given in regulation 6;”.

This modifies Regulation 2 of the original 2025 Regulations by changing how the term 'certification scheme' is defined.

It now explicitly directs readers to look at the meaning provided in the amended Regulation 6.

Regulation 4 amended (hybrid heating systems)6.

In regulation 4(1), in sub-paragraph (b)—

(a)

omit “both”,

(b)

for “and hot water heating”, substitute “whether or not it also provides hot water heating”.

This revises Regulation 4 concerning hybrid heating systems.

The word 'both' is removed from sub-paragraph (b), and the description of the system is changed to clarify that the system qualifies whether or not it is configured to also supply hot water.

Regulation 6 amended (approval of certification schemes)7.

For regulation 6, substitute—

“Certification scheme6.
(1)
The certification scheme is the Microgeneration Certification Scheme.
(2)
The Secretary of State may approve a subsequent version of the Microgeneration Certification Scheme as the certification scheme.
(3)
The Secretary of State, when exercising the power in paragraph (2), must publish—
(a)
the details of any subsequent version of the Microgeneration Certification Scheme which is approved under paragraph (2);
(b)
the date from which the subsequent version of the Microgeneration Certification Scheme is approved;
(c)
the details of any transitional arrangement to the subsequent version approved under paragraph (2).
(4)
In this regulation “Microgeneration Certification Scheme” means the scheme under that name operated by the MCS Service Company Ltd (a company registered in England and Wales with company number 07759366).”.

This extensively rewrites Regulation 6, establishing the Microgeneration Certification Scheme (MCS) as the official certification body for the CHMM in paragraph (1).

Paragraph (2) grants the Secretary of State the authority to approve future versions of the MCS. If the Secretary of State approves a new MCS version, paragraph (3) requires them to publicly publish the scheme details, the approval date, and any transition arrangements.

Paragraph (4) provides the formal definition and operator details for the MCS.