The work includes fitting three rooftop air source heat pumps, new heating emitters and replacing LED lighting throughout the building.

An 8,000-litre thermal store to optimise heating performance will also be installed and electrical infrastructure upgraded.

The project has been made possible by funding from the Public Sector Decarbonisation Scheme (PSDS).

The initiative helps public sector bodies decarbonise their property estates, primarily by switching older gas boilers to heat pumps.

A total pot of almost £5 million is being invested after the council's cabinet members agreed to provide a further £1.2m in February this year to enable the scheme to go ahead.

A report at the time said funding had to be spent by the end of March next year under the terms of an agreement.

Hannah Appleyard, the council's cabinet member for culture, leisure and sport, said: “We all know that energy costs continue to rise.

"These works will provide a more cost and energy efficient pool, meaning we can keep providing this important and high-quality service that I know so many of our residents use and enjoy."

George Ayre, portfolio holder for environment and civic services, said: “Sun Lane Leisure Centre is one of our most energy-intensive buildings.

"These works will make the building more efficient, reduce carbon emissions, and modernise it for the future.”

The work is being delivered by Alliance Leisure through the UK Leisure Framework, managed by Denbighshire Leisure Ltd on behalf of the Council.

The council said the centre will mostly remain open throughout, with a short closure when the new heating systems are switched over.

The upgrade is expected to be completed by March 2026.

For more information and the source, visit: Work underway on £5m green technology upgrade at leisure centre