A council is to continue with plans to “green” its two key buildings – but at a cost.

The project to decarbon Maidstone House and the Link Building in King Street, Maidstone will now cost over £1.54m more than originally expected – and may be as much as £2m more.

The two buildings accounted for 17.6% of the council’s carbon emissions during a study in 2022.

Maidstone council successfully applied for a government grant of £3.1m to retrofit Maidstone House with air source heat pumps, extra insulation, upgraded glazing and solar panels on The Link building.

It was estimated to save the council £51,875 and reduce its carbon production by 361.8 tons of CO2 per year.

The council was going to add £648,664 of its own money to complete the project which had been costed at £3.77m.

However, that estimate has soared to £5.32m due to changes in specification - a 41% increase.

The council also decided to add a 10% contingency to the £5.32 million, giving an updated cost for the decarbonisation project of £5.85m.

Usually the council expects to see a return of 5% on any capital investment, but the decarbonisation scheme will now provide only a 1.9% return.

Cllr Mike Summersgill is the cabinet member for nature transition and climate recovery.

He told his cabinet colleagues that the increased cost estimate was “due to various changes in material specifications and more detailed technical advice”.

His request that the expenditure be approved was agreed by cabinet members at their meeting last Wednesday without any comment or discussion.

The council expects to start construction on the project in January 2025.

It is a condition of the government grant that the money is spent by March 31, 2025.

After the meeting, opposition member Cllr Stan Forecast (Con) said: “Green energy and decarbonisation are important and should be aspiration goals.

After the meeting, opposition member Cllr Stan Forecast (Con) said: “Green energy and decarbonisation are important and should be aspiration goals.

“However, the UK contributes a mere 1% of global emissions.

“Given the current economic climate, MBC should be preserving taxpayers’ money for more real-life issues such as local housing, reducing the council tax burden, and regenerating our town centre. Sadly this decision is an inconsequential vanity project.”