Council saves £230,000 through installation of ground source heat pumps

 The Riverside Centre, an adolescent services office and, Stakeford Depot, a 3,000m2 council depot including offices and workshops, were identified by Northumberland County Council as being in desperate need of heating upgrades. Existing heating systems were failing, resulting in high running costs, high maintenance costs and poor comfort for the building occupants.

 and can be used in difficult situationsFollowing a rigorous approval process by the Council to ensure that ground source heat pump works would deliver cost effectiveness and environmental benefits, works were permitted to proceed.

The resulting works are estimated to be saving the council around £230,000 in running costs and will generate over £900,000 through the Non-Domestic Renewable Heat Incentive over 20 years.

The Riverside Centre is off the gas grid, and was heated by failing electric night storage heaters. As a result the building suffered from high running costs, poor comfort and high carbon emissions. The annual space heating demand was 32,000 kWh.Used by children’s services and the youth offending service, the building had to remain open at all times. As a consequence, with vulnerable people often on site, the internal installation programme was carefully designed with the building occupiers to minimise disruption.

At just under 3,000m2 the Stakeford Depot is the largest commercial premises to feature Kensa ground source heat pumps and has an annual heat demand of 320,000 kWh.

Unlike the Riverside Centre, the depot was heated by gas boilers. These had been failing for a number of years to such an extent that most offices had temporary electric heaters, while some even had permanent electric heaters installed. Consequently, running costs and carbon emissions were very high and occupant comfort was low. Consisting of a mixture of offices and workshops, during the works this building also remained occupied throughout the ground source heat pump works.

At each building a ground source heat pump system including boreholes and new wet heating system was installed and the old heating system was removed. Correct sizing of the heat pump and the heat emitters was achieved by carrying out detailed surveys to enable room specific heat losses to be calculated.

The internal works encompassed the installation of the ground source heat pumps within the plant rooms, including the installation of new pipework (re-using where possible), fittings, valves, pumps, and buffer vessels where required, new heat emitters (fan coil units and radiators), new wet heating distribution pipework, and of course the decommissioning and removal of the former heating system.

Great efforts were taken to minimise disruption and decoration post-installation as a consequence of the removal of the old system. Existing materials were used wherever possible, including distribution pipework, as well as sourcing new custom-built fan coil units to occupy the same footprint as the previous ageing models.

The full installation was designed to ensure that the systems met all eligibility criteria for the Non- Domestic Renewable Heat Incentive (RHI) and were successfully accredited.

 The estimated total benefits resulting from the ground source heat pump installations are:

  • Running cost savings of £240,000 over 20 years
  • RHI income of £900,000 over 20 years
  • Lifetime carbon emissions reduction of 1150 tonnes
  • NPV of the investment to be £96,000 after 20 years
  • IRR of 4.5% for Stakeford Depot, and 7.9% for the Riverside Centre

A small  part of the savings achieved have resulted from the installation of enhanced loft insulation.


The works at the Riverside Centre and Stakeford Depot have demonstrated that ground source heat pumps can become a mainstream heating solution for the thousands of public buildings that exist throughout the UK and can be used in difficult situations.