The authority has been awarded a huge government grant to pay for the bulk of the work on four leisure centres, its main Civic Centre headquarters and its council depot.
And cabinet members are expected to rubber stamp the project on Wednesday by approving a contribution of £500,000 from the council's own resources.
South Ribble was told recently it had won funding of almost £5m from the Public Sector Decarbonisation Scheme to carry out the work as part of its ambition to be carbon net zero by 2030.
The buildings involved - known as the Big Six - are Bamber Bridge, Penwortham and Leyland Leisure Centres, South Ribble Tennis Centre, the Civic Centre in Leyland and the Moss Side works depot.
To get the government funding all the work will have to be completed within 12 months, giving the council until the end of March 2023.
Work will include the provision of renewable energy, air source heat pumps, LED lighting and improving ventilation.
Cabinet members will be asked to agree total spending of £5,468,854 (including the council's contribution of £500,000). Highly-rated UK Leisure Framework has been awarded the contract.
A report to Wednesday's cabinet says: "The option of not committing to applying for the decarbonisation grant was considered, but it was agreed the time and effort in submitting the bid was worthwhile, and the potential benefits towards the council’s goal of net zero by 2030 was an opportunity that could not be missed.
"The decarbonisation works planned will significantly reduce the carbon footprint of the Big six key buildings within South Ribble Borough and will contribute significantly to the councils net zero carbon emissions target.
"As part of the conditions of the PSDS grant there is a need to delivery the improvement works and spend the money within the next 12 months. This is a particularly tight timescale and failure to deliver on the timescales would results in a non-compliance of the grant award conditions and potential result in non-payment of the grant funding."
Officers say the work will be carefully planned to minimise any disruption of closure of the buildings, particularly the leisure centres which are used daily by the public.