Private Housing Retrofit

Delivering retrofit ground source heat pump installations at scale is key to achieving our carbon reduction targets – 80% of the building stock that will exist in the UK in 2050 has already been built. By engaging the rented and owner-occupier sector to deliver community-wide ‘heat the street’ schemes, Kensa is future proofing our buildings of yesteryear.

British countryside village - Kensa Contracting


Kensa’s philosophy for retrofit private housing heating upgrades is for a street-by-street, area-by-area basis, rather than house-by-house. This approach has significant benefits, including:

Working in areas of a single decision maker, i.e. privately owned blocks of flats and estates, Kensa’s approach ensures government subsidy can allow large numbers of people to connect at the same time.


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 new builds:
  • Qualify for 20 years of income via the Non Domestic RHI;
  • Income certainty – RHI based on EPCs deemed heat consumption;
  • Split-ownership of ground arrays provides a funded option;
  • Exempt from Heat Network Metering & Billing Regulations;
  • Extremely low CO2 emissions;
  • Easy carbon & building regulations compliance;
  • 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.

Why Choose Shared Ground Loop Arrays?


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.


Renewable Heat Incentive (RHI)

Shared Ground Loop Arrays are eligible for 20 years of guaranteed quarterly payments via the Non Domestic RHI.

The 2018 RHI Regulations included an important refinement; for the first time, Non Domestic RHI quarterly payments for residential properties linked to Shared Ground Loop Arrays are now based upon the deemed heat consumption taken from the Energy Performance Certificate.

By introducing deemed payments for the Non Domestic RHI and allowing ‘split ownership’, Government has created a significant catalyst for energy efficient heating upgrades in private housing featuring Shared Ground Loop Arrays, with costs no longer borne by the housing provider.

This key change:
  • Reduces capital costs (as meters are no longer needed) and eliminates all the administration burden linked to quarterly readings and submissions.  More importantly, it has prompted funders to back Kensa Utilities’ offer of ground arrays at no charge to the homeowner.
  • 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 homeowners fund the heat pumps (which is sold with the property and maintained by the homeowner) whilst the ground array is fully funded.

Typical Project Costs

Financial illustration (retrofit of 24 houses):

Based on Kensa’s fully funded ground arrays option.

Total Cost of Installation (Paid by Homeowners)£432,270
Kensa Utilities Capital Contribution (RHI-linked)£229,079
Net Cost of Ground Source Heat Pumps & Cylinders*£203,190
*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.


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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  • 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.

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:

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.


house purchasers

Free 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.

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