Social Housing Retrofit

Kensa works closely with social housing providers to deliver a sympathetic programme of retrofit ground source heat pump installations with minimal disruption and major benefits, reducing tenant bills and making a dramatic impact on fuel poverty reduction.

Enfield Ground Source Heat Pump Tower Blocks Upgrade Combats London Air Pollution


By pairing Kensa’s Shoebox heat pumps with Shared Ground Loop Arrays, developments featuring multiple dwellings, including flats, can attract external funders to own and operate the ground source heat pump infrastructure, removing the cost of the shared ground loop array from the housing association. In return, the external funder can charge connection fees if they wish.

System Architecture

Mimicking a traditional gas framework, Kensa’s innovative Shared Ground Loop Arrays link a series of boreholes to multiple properties via an ambient temperature distribution system.

Each property then has an individual Kensa Shoebox heat pump wired to their own electricity supply, which upgrades the low temperature heat for heating and hot water within their dwelling.

Shared Ground Loop Array Kensa Shoebox ground source heat pump in housing

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The advantages of Shared Ground Loop Arrays in retrofits:
  • Split-ownership of ground arrays provides a funded option;
  • Exempt from Heat Network Metering & Billing Regulations;
  • Extremely low CO2 emissions;
  • No NOx, SOx or particulates emissions;
  • Lowest energy bills – slightly lower than mains gas, significantly lower than air source heat pumps, LPG & oil;
  • Householders able to switch energy suppliers;
  • No district heat losses;
  • Potential for free summer cooling;
  • Scalable and flexible district size can be deployed in sections as the development progresses;
  • Ultra-efficient and reliable.


The Kensa Shoebox Series

Shoebox Heat Pump with plug

  • Suited to flats and apartments and smaller houses.
  • Available in 3 – 6kW.

Hot Water Cylinder & Thermal Store

cylinder and sunamp

  • Sunamp’s super-compact Heat Battery technology fits perfectly with the Shoebox heat pump to provide a clean, efficient and cost-effective thermal energy storage solution.
  • Kensa has partnered with leading cylinder manufacturer, Advance Appliances, to design and produce stainless steel mains pressure cylinders featuring enhanced surface area coils specifically for ground source heat pumps.


Energy Company Obligation (ECO)

Ground source heat pump installations are eligible for ECO funding in retrofit social housing schemes.

ECO places legal obligations and targets on the larger energy suppliers to fund energy efficiency measures in British households.

It is in place to support retrofit efficiency works in the domestic sector, with a particular focus on vulnerable consumer groups and hard-to-treat homes.


Under the rules of ECO, energy suppliers are obliged to fund energy efficiency improvements of their domestic customers’ buildings in three distinct areas; Carbon Emissions Reduction Obligation (CERO), Community Obligation (CSCO), and Home Heating Cost Reduction Obligation (HHRCO).


Split Ownership model

By allowing ‘split ownership’, Government has created a significant catalyst for energy-efficient new build developments featuring Shared Ground Loop Arrays, with costs no longer borne by the housing provider.

This eliminates the key barrier to deployment – the expense of the ground array – and allows Kensa to mimic long-standing ‘split ownership’ arrangements in the gas sector with the underground infrastructure owned and maintained separately from the heat pump installed inside the properties.  Kensa’s model sees the housing provider fund the heat pump (which is sold with the property and maintained by the purchaser) whilst the ground array is fully funded.

Typical Project Costs

Financial illustration (retrofit of 28 houses):

Based on Kensa’s fully funded ground arrays option.

Total Cost of Installation (Paid by Housing Association)£419,750
Net Cost of Ground Source Heat Pumps & Cylinders*£168,425
*Avoided costs should be subtracted from this figure. The deduction or counterfactual should include the costs of replacing the existing heating with night storage heaters or a boiler.
Please note: The Non-Domestic RHI has now ended. Visit Kensa Heat Pumps to explore current funding options.
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The below outlines the mechanism for housing providers wishing to utilise Kensa’s fully-funded Shared Ground Loop Arrays:


Kensa Ambient Shared Ground Array Funding Mechanism

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Case Studies: Apartments

Two Storey Flats

  • Project partnership with Hanover Housing Associations
  • 23 properties and a site office over two-storey flats
  • 12 x Shared Ground Loop Arrays
  • Kensa Shoebox 6kW Twin per flat
  • Replacing old inefficient night store heaters
  • Funded by the ECO grant
  • Completed in 10 weeks
  • Winner: Retrofit Project of the Year (H&V News Awards 2017)
  • Winner: Most Innovative Retrofit Scheme (Housing Innovation Awards 2017)

Low Rise Apartment Building

  • Project partnership with  Trent & Dove Housing
  • 60 properties in two blocks of three-storey flats
  • 12 x Shared Ground Loop Arrays
  • Kensa Shoebox 6kW Twin per flat
  • Replacing old inefficient night store heaters
  • Funded by the ECO grant
  • Winner: District Heating Project of the Year (H&V News Awards 2017)
  • Winner: Best Client (National Housing & Maintenance Forum 2016)

Case Studies: Housing

Ground Source Review Coastline, Wheal Vyvyan 4

Sheltered Housing

  • Project partnership with Coastline Housing
  • 12 bungalows
  • 3 x Shared Ground Loop Arrays
  • Kensa Shoebox 3kW per bungalow
  • Replacing old inefficient night store heaters
  • Funded by the ECO grant & Central Heating Fund (CHF)
  • Winner: Best contribution towards the creation of a sustainable energy economy (Cornwall Sustainability Awards 2017)
  • Winner: Overall Winner (Cornwall Sustainability Awards 2017)
  • Winner: Best Renewable Energy Scheme (Regen SW Green Energy Awards 2016)
  • Winner: Sustainable Project of the Year (HVR Awards 2016)
  • Winner: Large Scale Project SW Region (Energy Efficiency & Retrofit Awards 2016)

General Needs Housing

  • Project partnership with the Flagship Group
  • Mixed development of houses, bungalows and flats
  • 5 x Shared Ground Loop Arrays
  • Kensa Shoebox 6kW per dwelling
  • Replacing electric panel heaters
  • Funded by the ECO grant
  • Completed in 9 weeks
  • Shortlisted for Non-Domestic Ground Source Heat Pump Project (ACR & Heat Pump Awards 2017)
  • Shortlisted for Best Contract, National Housing & Maintenance Forum (NHMF Awards 2017)


  • 5 year warranty for the heat pump unit.
  • 2 year warranty for the controller and water pumps.
  • 2 year internals warranty.

Extended warranties are available on request.

User Engagement

Kensa Contracting offers a comprehensive information and training programme to support residents, Housing Association staff, project and scheme managers, ensuring all stakeholders are engaged and well-prepared and understand the stages of work involved.

After Care & End Users

Property’s featuring Kensa’s Shared Ground Loop Arrays will provide end users with numerous unique benefits over traditional Heat Networks with minimal after care requirements:

Lower fuel bills

GSHP’s produce 3-4kWh of heat energy for every 1kWh of electrical energy used, making them 300-400% efficient. Compare this to a typical boiler, which is just 90% efficient. Kensa’s ground source heat pump systems offer the lowest fuel costs.

Lower emissions

Because a GSHP extracts so much “free” energy from the environment, this enables CO2  emissions to be lower than any other type of heating system.

Minimal maintenance

GSHP’s don’t require annual servicing or maintenance, and have an expected lifetime of 20 years.

Energy independence

With an individual ground source heat pump in each property, homeowners are in complete control of their own heating and energy bills, enabling easy energy tariff switching and payment only for their own heat consumption.

Download End User's Guide

house purchasersFree cooling & no overheating

With heat being generated at the point of use (inside each dwelling) the ‘heat’ circulating the property is low temperature, therefore there are no heat losses from the system to contribute to overheating in risers and corridors. The low temperature system also allows for free passive cooling to be introduced, creating a comfortable living environment all year round.

Year round supply

1m below the surface the ground temperature remains a fairly constant 8-10°C all year round, ensuring your heat supply is constant and reliable; unlike air source heat pumps, which are impacted by external fluctuating air temperatures causing higher bills when heat is most needed.


Find out more about Kensa’s ground source heat pump solutions for social housing by clicking the links below:

Kensa Heat Pumps and Hanover win Retrofit Project of the Year at the H&V News Awards 2017

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