You must must report your fossil fuel boiler sales if youre classed as a scheme participant or near-threshold supplier in the CHMM. Check if the CHMM applies to you and the timelines for action. Scheme participants and near-threshold suppliers must
Scheme participants must also send an annual report of their fossil fuel boiler sales and a third party verifiers assurance report. Check how to register and report using the Manage the Clean Market Mechanism M-CHMM service. When recording and excluding fossil fuel boiler sales, you should consider the definitions of a fossil fuel boiler sale and an excluded sale in the CHMM Regulations Reg 21. The annual report should include evidence supporting the exclusions of any fossil fuel boilers. Exclusions include boilers exported outside the UK.
It also includes boilers installed in new buildings that were not used or occupied before the installation took place. Quarterly sales data
Scheme participants and near-threshold suppliers must send quarterly data on the number of
Send this data through the M-CHMM service within 28 days of the end of the quarter. You do not need to send a verifiers assurance report with the quarterly data. Email chmmenvironment-agency.gov.uk to request a copy of a boiler reporting template. This template will help you gather all the required fossil fuel boiler sales data. This reduces the need for the Environment Agency to contact you to request more information. You must keep records if youre a scheme participants or near-threshold supplier. This is so you can prove that you have fulfilled your CHMM obligations see Maintenance of records section. The Environment Agency may request these records at any time. Make sure you keep records of
Annual sales data
Scheme participants must send their annual fossil fuel boiler sales data and the documents that go with this through the M-CHMM service. You must do this by 30 June after the end of the scheme year. The annual fossil fuel boiler sales data must include the number of
You can use the same boiler reporting template for both the annual and quarterly fossil fuel boiler sales data. You must send the annual fossil fuel boiler sales report with
You should prepare for the annual report in the final quarter of the sales year to give enough time to
Supporting evidence
Scheme participants must send supporting evidence confirming their annual fossil fuel boiler sales data submission. You will need to upload this supporting evidence alongside the annual boiler sales data as one or more attachments. The supporting evidence can be in any format that the Environment Agency can use. However, it must be comprehensive and correct to show thorough reporting.
The data should show how it was gathered and checked for accuracy. It should also allow the Environment Agency to trace excluded fossil fuel boiler sales. As part of the third party verification process, your verifier will ask you to give evidence to confirm the accuracy of your fossil fuel boiler sales data. They will also ask for any exclusions you have applied to your fossil fuel boiler sales. Your verifier must decide what evidence is enough to support verification. You will need to send this evidence of accuracy with your annual fossil fuel boiler sales data. The Environment Agency will decide if you have given enough evidence. Verifiers assurance report
Scheme participants must appoint an independent verifier to verify their annual fossil fuel boiler sales report. The verifier must meet all these criteria
The verifiers must give their views on if the
You must give your verifier the information they need to complete their work. Youre responsible for sending the verifiers assurance and sending your annual fossil fuel boiler sales to the Environment Agency as CHMM scheme administrator. You must also send the supporting evidence for any excluded sales. The Environment Agency will publish guidance on third party assurance later in 2025. Power to estimate boiler sales data
The Environment Agency may work out determine your qualifying and excluded fossil fuel boiler sales if
They will use this when recording your low-carbon heat target. If you become aware of an error after submitting your data, you must tell the Environment Agency. They will review the data and, if needed, update the M-CHMM service. If the error is important and relates to the annual sales data, they may request another verification report.
Maintain records and audits
You must
The Environment Agency may ask to check this data at any time. Low-carbon heat targets
Scheme participants will have a low-carbon heat target. These are based on a percentage of their fossil fuel boiler sales which exceed the threshold. The CHMM Regulations give the relevant percentages as
The percentages for scheme years 2 and beyond are set by the Secretary of State. The Environment Agency will calculate your low-carbon heat target after they
There will be a low-carbon heat target for each scheme year. This will be based on combined annual fossil fuel boilers sales above the threshold of 19,999 gas boilers and 999 oil boilers. This figure will be multiplied by the percentage. This is the number of CHMM credits that you will need to meet your low-carbon heat target. Example
A scheme participant with qualifying sales of gas boilers of 30,000 and with qualifying sales of oil boilers of 2,000, would have a CHMM target for that year of
30,000 19,999 2,000-999 6
10,001 1,001 6 660.12
CHMM target of 660
Where the target is not a whole number, the Environment Agency will round this up or down to the nearest whole number. Carry forward a low-carbon heat target
At the end of a scheme year apart from 2028, a scheme participant that does not have enough CHMM credits can carry forward part of its target to the next scheme year. This must be up to the greater of
Example
A scheme participant whose qualifying sales were 30,000 gas boilers and 2,000 oil boilers and has a CHMM target of 660 as shown above. The carry forward available based on each of the previous bullet points is the greatest of
The maximum permitted carry forward for this scheme participant is 300. If this scheme participant got 600 credits from heat pump installations and credit transfers, this would result in a target shortfall of 60 credits. As the shortfall is less than 300, the scheme participant can carry forward the whole target shortfall 60 to meet in the next scheme year. The shortfall will be added to the next years target. You can only carry a shortfall forward by one scheme year.
The Environment Agency will apply the maximum carry forward. That is unless you contact them by 1 October after the relevant scheme year to
Credits and payments
The M-CHMM service gives credits for certified retrofit installations of heat pumps. To lead to a CHMM credit, the installation must be recorded on a registry of an approved certification scheme. It is anticipated that from 1 April 2025, the Microgeneration Certification Scheme MCS will be approved as a certification scheme for the CHMM. MCS will issue certificates, and these will appear in your CHMM account as CHMM credit.
The Environment Agency matches data on the MCS installation database of certified installs with M-CHMM accounts. You need to keep the Environment Agency up to date with the brand names that apply to your heat pumps. You can view your credits in the M-CHMM service. Getting a CHMM credit
You can get CHMM credits if youre the manufacturer of a heat pump which is notified under an approved certification scheme as having been installed. The installation of one standalone heat pump will lead to one CHMM credit. The installation of a hybrid heat pump will lead to half a CHMM credit. Credit holders that want to trade CHMM credits must first register on the M-CHMM service. Transferring credits
Scheme participants may not have enough CHMM credits to meet their low-carbon heat target. Other scheme participants or credit holders who are not participants may have a surplus of credits, and so may want to transfer credits to other participants. Only scheme participants can get CHMM credits through a credit transfer. The M-CHMM service has a list of parties who have shown an interest in transferring CHMM credits. This list is not exclusive, and they dont have to be on the list to transfer credits. The list is to help connect people. You must complete the financial and contractual aspects of credit transfers outside of the M-CHMM service. The Environment Agency will not be involved in this process. You must only transfer credits in the M-CHMM service after agreeing terms between the 2 parties. The M-CHMM service gives guidance on how to transfer CHMM credits. The CHMM credit transfer period is 1 October of the scheme year to 30 September of the year after. Surrendering credits
Scheme participants must surrender credits by 1 October after each scheme year. There should be enough surrendered CHMM credits to meet your low-carbon heat target. One CHMM credit is equal to one unit of the low-carbon heat target. Carrying over credits
At the end of each scheme year, you can carry over some surplus CHMM credits those not surrendered or transferred to the next scheme year. A scheme participant can carry over up to 10 of its CHMM credits before surrender. A credit holder can carry over up to 10 of its CHMM credits for the year. Example
If a scheme participant has 460 credits, but a CHMM obligation in year 1 of 440 credits, they can carry over their full surplus of credits 20 credits to year 2. This is because the amount 20 is less than their allowed maximum of 46 credits 460 x 10 that you can carry over to year 2. If the same scheme participant got 600 credits in year 1, they would only be able to carry over 60 credits 600 x 10 to year 2. The Environment Agency will apply the maximum carry over, unless you contact them by 1 October after the relevant scheme year. Credit expiry
On 1 October after the scheme year, CHMM credits will expire if you have not
Payments
If you do not have enough CHMM credits, including after applying any target carry forward, you will need to pay to cover the difference. You need to pay 500 for each CHMM credit. The Environment Agency will send you a notice showing the amount to pay, with instructions. You will need to pay the Environment Agency as scheme administrator by 30 November after the end of the scheme year. How to register
Register and report your data using the M-CHMM service. How youll be regulated
Check how compliance, enforcement, and appeals work. For help
Contact chmmenvironment-agency.gov.uk if youre unsure if the CHMM applies to you.