All modifications to the Heat Trust Scheme are undertaken according to the processes set out in paragraph 17 of the Scheme Bye-Laws.

If you would like to submit a proposal to modify the Heat Trust Scheme please submit your proposal in writing to the Scheme Administrator by completing a modification proposal form and returning it to This email address is being protected from spambots. You need JavaScript enabled to view it..

Below is a list of modifications implemented to date, with links to their reports showing the full process (please click on the title in orange):

  1. Modification to Refunds
    1. The Modification on Refunds is to amend timeframe of refunds to 10 business days from calendar days.
  2. Modification to Fault Response Times
    1. The Modification to Fault Response Times is to standardise fault response times across seasons.
  3. Modification to Heat Customer Supply Arrangements
    1. The Modification to Heat Customer Supply Arrangements is to allow heat networks that do not use individual Heat Energy Supply Agreements to apply to register with Heat Trust, provided that clear terms of service are provided within a separate document, e.g. a customer charter and additional evidence
    2. Report on Consultation for Heat Customer Supply Arrangements
  4. Modification to Reporting Requirements
    1. The Modification to reporting requirements adds debt, resumption of supply and Guaranteed Service Payments to the six-monthly data submissions by Registered Participants.
  5. Extending the 5year audit deadline due to Covid-19
    1. The Modification extended the deadline in Section 11 of the Bye-Laws by when audits of Registered Sites must be completed, in response to disruption cause by Covid-19 with approval by the Board.

Modifications approved as part of the Scheme Rules Review relating to vulnerable customers:


MOD017: Metering and billing clarifications
to clarify that amendments to the Heat Networks (Metering and Billing) Regulations are included where the regulations are referenced; to clarify that advice should be on both Heat Bills and Annual Account Statements; and to only include advantages and disadvantages of pre-payment meters where customers have a choice of meter type.

MOD021: Reducing the minimum consultation period for modifications - Scheme Bye-Laws change
to shorten the minimum required consultation period for modifications specified in the Scheme Bye-Laws from 12 weeks to 8 weeks, to enable modifications to progress faster if appropriate.

MOD014: Meter reading with AMR
to clarify that suppliers should inform customers how to manually read AMR meters in case of failure, and to add a requirement for suppliers to use actual meter readings for every bill where there is AMR

MOD013: Treating customers fairly
to introduce a requirement for all Registered Participants to treat their customers fairly

MOD022: Audit and compliance
To improve efficiency and reduce regulatory burden and cost of the Heat Trust audit process. To update Scheme Bye-laws in order to make the Scheme Administrator the final decision maker at all stages of the audit process. To update Scheme Bye-laws to enable the Scheme Administrator to trigger audits of bespoke scope and in an increased number of circumstances should it be appropriate to do so. To remove the pass / fail criteria in the audit process and instead focus on remediation of any non-compliance found. To introduce Scheme Bye-laws to require Registered Participants to provide information reasonably required by the Scheme Administrator in order to assess compliance with the Scheme Rules.

MOD020a: Indexation of minimum Guaranteed Service Payment (GSP) amounts
To simplify the process of upgrading the amount of Guaranteed Service Payments (GSPs) in line with inflation (indexation).

For open modifiations please see here.

For consultations on potential future modifications or changes please see here.