Heat Trust aims to protect thousands more customers who receive heat through the district heating sector as it has extended its eligibility requirements.
The customer protection scheme says more people will be able to access free, independent complaint resolution and minimum customer service standards.
To date, heat network suppliers have been required to have a heat energy supply agreement in place with each customer before being eligible to register.
The change will enable existing heat network suppliers, that do not have such an agreement, to register with Heat Trust if they have a customer charter or equivalent.
Bindi Patel, head of scheme at the Heat Trust said more than 37,000 customers were already benefiting from being on heat networks registered with the trust and thousands more customers could now have the same protection as a result of the change.
She said: “The change recognises that many heat network suppliers, particularly housing authorities and local authorities, often capture heating and hot water provision in tenancy or leasehold agreements as opposed to a specific heat energy supply agreement.
“By opening up eligibility to these operators who can demonstrate they have clear commitments to specific service standards and terms and conditions in place, we are able to offer Heat Trust benefits to thousands more customers on heat networks across the UK.”
Virginia Graham, of the Renewable Energy Consumer Code (RECC), added: “By enabling more heat networks to register with Heat Trust, thousands more customers will be given an assurance dependable heat supplies and high-quality service.”