How much will a ground source heat pump slinky system cost for a commercial building?

In this example, a cascaded ground source heat pump system fed by a slinky ground array, could cost in the region of £87,000 to £115,000, and earn between £350,000 to £500,000 income from the Non Domestic Renewable Heat Incentive (RHI).

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Example: Project & Finances

Kensa has calculated example costs to illustrate the upfront finance required for a cascaded ground source heat pump system and slinky ground array for a commercial building, compared to an LPG system.

Expected running costs and Non-Domestic Renewable Heat Incentive (RHI) income are also included.

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Heat Pump Specification

System architectureCascaded central plant
Total heat pump capacity120kW
Equipment type3x 45kW Plant Rooms
Design conditions0/50°C
Potable DHW tempSpace heating only
Integral immersion heatersNo (DNO friendly)
Ground array typeSlinkies
Slinkies requiredx24, plus header pipework
Land area required6000sq/m


Total Project Costs, Savings & Returns vs LPG

SystemKensa Ground Source Heat Pump & Ground ArrayLPG Boiler
Lifetime Expectancy: ApplianceUp to 20 yearsUp to 10 years
Lifetime Expectancy: InfrastructureUp to 100 years-
Carbon Saved (over 20 years)800 tonnes0 tonnes
Local NOx emissions*0kg NOx/y12.09kg NOx/y
Appliance & Infrastructure Cost**£87K to £115K£7K
Running Costs (over 20 years)***£350K to £400K£450K to £500K
Servicing Costs (over 20 years)****£0£2K
Non Domestic RHI Income (over 20 years)*****£350K to £500KNot eligible
Net cost (after 20 years)******£15K - £87K£459K - £509K
*NOx emissions based on 56mg/Kwh for gas and liquefied petroleum gas (LPG) boilers (1800 run hours) **Costs are for the supply and installation of the Kensa heat pump and ground array only, and the supply and installation of the LPG boiler equipment only. Costs for supply and installation of internals such as radiators, underfloor and heating controls are not included, please speak to your plumbing contractor. ***Based on electric at 15p/kW/hr and COP of 3. Based on LPG at 40p a litre and 85% efficiency ****Ground source heat pumps have no requirement for annual maintenance. However, it is good practice for the heating distribution system to be proactively checked and maintained to ensure optimum performance. *****The NON-DOMESTIC RHI is a 20 year index linked funding stream which assumes inflation at 3%. ******Net cost for LPG does not include an additional LPG boiler, which will likely need to be  factored in during the 20 year comparison period due to the LPG’s 10 year average lifetime expectancy.

Example: Schematic

For illustrative purposes only

Case study: Hornsea Garden Centre

Hornsea Garden Centre near Hull has three Kensa Plantroom heat pumps installed in a cascaded system to provide heating and hot water to a large new-build extension with 30,000 sq ft of retail space and a café kitchen.

Key facts:

  • New-build extension providing 30,000 sq ft of retail space;
  • Main building upgraded to underfloor heating;
  • Cascaded system architecture;
  • 2x 45kW Plantroom Heat Pump providing space heating;
  • 1x 25kW High Temperature Twin Compact Heat Pump providing hot water;
  • 24x 50m slinkies located under nearby field;
  • System contains 7250 litres of water and 1450 litres of antifreeze.
Read more
Garden centre entrance

Case Study: Todridge Farm

The owners of Todridge Farm had four 21kW Kensa Hybrid Heat Pumps installed in a cascaded system to cover the high demand for heating and hot water in their six bedroom farmhouse and four adjacent cottages.

Key facts:

  • 6 bedroom farmhouse and 4 cottages – 700m²
  • Displacing oil heating
  • x4 21kW Kensa Hybrid Heat Pumps
  • Cascaded system architecture
  • Pipework sunk into flooded marshland
  • Funded by the Renewables Finance Loan and Non Domestic RHI
Read more
Housing Heating Network

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Related Content

Blog: Cascaded ground source heat pumps

If a commercial premises has a high demand for heating and hot water, then modular cascaded ground source heat pumps provide an effective solution to meet the heat load of the property.