Introduction
The Church of England has set an ambitious target: achieving net zero carbon emissions by 2030. For many churches, heating is one of the largest contributors to their carbon footprint. Installing a heat pump system is a powerful step towards meeting this target and also contributes to the Eco Church award scheme run by A Rocha UK. In the "Buildings and Energy" section of the scheme, renewable heating technologies such as heat pumps can help churches move toward a Gold award.
This guide is based on the recent work undertaken at St John’s Church in Egham, where VitoEnergy led a complex but ultimately successful decarbonisation project. By sharing the lessons learned, we aim to support other churches in navigating the challenges and opportunities that come with heat pump installations.
1. Understanding the Bigger Picture
Moving away from fossil fuels not only supports climate goals but also future-proofs church buildings against rising energy costs and tightening regulations. Heat pumps are an efficient and sustainable option, especially when designed carefully around a church's intermittent use pattern.
At St John’s, the decision to move to a heat pump system was part of a broader commitment to environmental stewardship. This was supported by the availability of grant funding and a clear opportunity to improve long-term resilience.
2. Initial Scoping and Feasibility
Early engagement with experienced contractors is key. Site surveys should assess:
- Electrical supply capacity (e.g., availability of 3-phase power)
- The condition and layout of existing heating systems
- Usage patterns and heat-up time requirements
- External restrictions around locating a heat pump and environmental impact
Understanding these parameters upfront helped avoid costly surprises at St John’s and enabled an optimised system design.
3. Planning Permission and Approvals
For most churches, both faculty consent and local authority planning permission will be required. Key issues that often arise include:
- Aesthetics and visual impact
- Proximity to trees and archaeological sites
- Sound levels from external units
At St John’s, early pre-planning discussions with Runnymede Borough Council were helpful. However, even with initial support, questions around tree root protection, trench depth, and equipment access required expert input and careful documentation.
Maxa air source heat pumps were selected for this project
4. Design and System Considerations
Heat pumps operate at lower flow temperatures than gas boilers, meaning that the size and output of radiators (emitters) becomes more critical. In some cases, pipework and circulation pumps may also need upgrading.
Key lessons from St John’s:
- Underfloor heating zones required updated manifolds and controls
- Flow temperatures must be carefully balanced to ensure comfort
- Zoning controls enabled selective heating (e.g., church vs meeting rooms)
VitoEnergy also explored the pros and cons of using two vs three external heat pump units. Three offered better redundancy and flexibility but required more space and planning negotiation.
5. Practical Installation Logistics
Church grounds pose unique challenges, from limited access to the need to preserve heritage features. At St John’s:
- Equipment weighing over 280kg was delivered via trolleys to avoid tree damage
- Gravel bases with paving stones were installed to avoid using chemicals (concrete) in order to reduce the risk towards the trees and root systems.
- Trenching had to be shallow in places, using concrete duct protection where necessary. Because the tree advisers want us to avoid the roots the trench may well now be a meter deep and the team must avoid cutting anything over 25mm in diameter.
Forward planning on access width, vehicle requirements, and lifting gear made the process smoother.
6. Tree Roots and Archaeology
With historic grounds and mature trees, special measures were taken to avoid root damage. These included:
- Tree surveys and protection methodologies
- Coordination with diocesan and local archaeological bodies
- Avoiding deep trenching near root zones or using surface-level alternatives
- Utilisation of existing route next to downpipe waste
These steps helped the project secure planning approval and maintain good relationships with local authorities.
7. System Integration and Controls
Installing a heat pump isn’t just about placing outdoor units. Internal components like heat exchangers, buffers, and control systems must be carefully integrated. At St John’s:
- The crypt was used for housing internal kit
- Controls allowed remote access and zoning
- Legacy issues such as failing mixing valves were addressed as part of the upgrade
Cleaning, flushing, and protecting existing circuits was essential to long-term performance.
8. Financial Planning
While initial grants from the Church of England didn’t materialise, St John’s secured alternative funding. Clear separation of costs between the renewable installation and general system upgrades proved valuable.
Advice includes:
- Explore both faith-based and secular grant options
- Separate VAT-exempt renewable work from taxable general plumbing
- Reduce contingencies as designs and permissions become clearer
9. Service, Maintenance, and Long-Term Support
A service contract ensures efficiency and peace of mind. VitoEnergy provided a clear estimate for annual maintenance and confirmed the availability of spare parts (with supplier support from Go-Geothermal).
Digital controls and remote monitoring also reduced the need for on-site diagnostics.
Consideration may be made in the future to supplement the heat pump installation with solar and batteries which will reduce the running costs by self generating and storing off-peak power at night for use in the daytime when power is more expensive.
10. How VitoEnergy Can Help
VitoEnergy specialises in low-carbon heating solutions, offering:
- Expert site surveys and feasibility assessments
- Full design and installation services
- Support with planning, permissions, and grant applications
- Long-term servicing and optimisation
Our experience with St John’s demonstrates our commitment to helping churches decarbonise without compromising on comfort or heritage.
Conclusion
Decarbonising a church building may seem daunting, but with the right guidance and partners, it is entirely achievable. We hope this guide provides a useful roadmap and encourages more churches to take confident steps toward sustainability.
To discuss your church’s potential project, contact the VitoEnergy team at www.vitoenergy.co.uk or call us on 01252 596300.
