27 May 2025
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Emma Bohan, Managing Director of IMS Heat Pumps/Geowarmth and Vice-Chair of the Ground Source Heat Pump Association, discusses overcoming challenges and the benefits of Ground Source Heat Pumps (GSHPs) in settings ranging from contemporary homes to centuries-old estates.
As the UK accelerates toward its net zero targets, decarbonising heating in existing buildings remains critical — especially within the often-overlooked category of heritage properties. Traditionally reliant on oil, LPG, or electric systems, these buildings present both challenges and unique opportunities.
While not always at the forefront of mainstream campaigns, GSHPs are proving to be a quiet revolution — discreet, efficient, and reliable in settings ranging from contemporary homes to centuries-old estates.
Why GSHPs make sense for heritage Buildings
GSHPs extract low-grade heat from the ground using buried pipework — either through horizontal trenches or vertical boreholes. That heat is compressed and upgraded for use in space heating and hot water. Their impressive efficiency — often achieving Seasonal Coefficients of Performance (SCOP) between 3.5 and 4.5 — makes them a compelling option for off gas-grid heritage sites.
Key benefits include:
- Up to 400% efficiency
- Stable, year-round performance
- Silent operation with minimal aboveground footprint
- Lifespan of 20–25 years for the unit, and over 50 years for the ground array
These features are particularly relevant in listed or conservation properties where visible alterations are restricted.
Debunking the myth: Heat pumps and heritage don’t mix
There remains a widespread myth that older buildings and modern renewable systems are incompatible. However, research and practice are steadily proving otherwise.
A 2023 report by Historic England, "Heat Pumps in Historic Buildings1”, concluded that both air and ground source systems can work in listed properties — with careful planning and sensitivity to the building’s fabric and layout. Similarly, the Electrification of Heat Demonstration Project2, led by Energy Systems Catapult, trialed heat pumps in homes across the UK — including pre-1919 properties. The results? Heat pumps are suitable for all property types, provided design and installation are done to high standards.
We’ve seen first-hand how ground source systems can deliver comfort and carbon savings without compromising heritage. When done right, heat pumps are absolutely compatible with even the most sensitive buildings.
Real-world results: GSHPs in heritage settings
TIXALL GATEHOUSE – A landmark project in every sense
Tixall Gatehouse3 is a spectacular Grade I listed building set in open Staffordshire parkland. Built around 1580 and described as “one of the fairest pieces of work made of late times in all these counties,” the building is the last surviving element of Tixall Hall. Once a prison for Mary, Queen of Scots and now owned by the Landmark Trust, the gatehouse is undergoing major renovation — including the installation of a discreet, low-carbon GSHP system, designed and installed by IMS Heat Pumps. System overview:
• 5 vertical boreholes
• 2 × NIBE F1156 18kW units
• 300L hot water cylinder and 220L buffer tank
• Underfloor heating to support low-temperature distribution
This installation respects the building’s layout and heritage while dramatically improving comfort and sustainability for future use.
CAMBRIDGE TERRACE – Grade I listed london residence
Part of John Nash’s iconic terraces in Regent’s Park, Cambridge Terrace4 has been converted into the largest private residence in London after Buckingham Palace. A GSHP system was installed to provide both heating and cooling, using a thermal bank approach — storing heat in the ground during summer and recovering it in winter. The system meets the property’s demanding environmental and comfort requirements while remaining invisible to the surrounding historic façade. With limited options for external plant, the underground solution proved ideal for a high-spec, low-carbon retrofit in a protected location.
MUNCASTER CASTLE – Flagship installation in a Living Estate
Home to the Pennington family for over 800 years, Muncaster Castle5 in Cumbria needed a heating solution that aligned with its sustainability goals. A GSHP system using vertical boreholes was installed to serve both the castle and adjacent estate buildings.
Despite being featured in a government heat pump campaign — mistakenly represented as an air source installation — the site in fact runs on a ground source system. The project stands as a prime example of low-carbon infrastructure working seamlessly within a Grade I listed, multi-building estate.
Technical considerations for installers
Working with heritage buildings requires a tailored approach:
• Heat loss assessment: Use dynamic modelling; fabric upgrades may be limited
• Flow temperature design: Low-temp systems (35–45°C) suit UFH and modern radiators
• Ground array design: Horizontal loops are best where land is available; boreholes offer
compact alternatives
• Planning & consent: Engage with conservation officers early
• Distribution options: Use low-flow radiators when UFH isn’t viable
Respecting interior aesthetics: Heating with style
Where underfloor heating isn’t feasible, traditional cast iron radiators can be retained or upgraded. A wide variety of modern cast iron-style radiators now combine classic looks with compatibility for low-temperature systems — offering both efficiency and visual harmony within historic interiors.
Support schemes and financial incentives
In England and Wales, the Boiler Upgrade Scheme (BUS) offers up to £7,500 toward GSHP installations. In Scotland, Home Energy Scotland provides grants and interest-free loans. These schemes make ground source solutions financially viable, particularly for off-gas-grid heritage properties.
Conclusion: A compatible future
The belief that heat pumps and heritage don’t mix is rapidly being dismantled. With careful planning, sensitivity, and the right expertise, GSHPs can meet the comfort and carbon goals of even the most historically significant sites.
Whether a castle, city terrace, or countryside gatehouse, Ground Source Heat Pumps represent a future-ready, heritage respecting solution. As retrofit technology improves and more successful heritage projects are completed, the sector is steadily shifting from resistance to confidence. Demonstrating what’s possible in buildings like Tixall Gatehouse or Muncaster Castle is helping to pave the way for wider adoption across the country.
Source
1. https://historicengland.org.uk/imagesbooks/publications/air-source-heat-pumpshistoric-buildings
2. https://es.catapult.org.uk/project/ electrification-of-heat-demonstrationproject/
3. www.imsheatpumps.co.uk/case-studies
4. www.icax.co.uk/Cambridge_Terrace_NW1
5. www.historichouses.org/sustainableenergy-at-muncaster-castle
