St John’s College Decarbonisation Plan
Client: St John’s College
The brief
St John’s College, Oxford, has committed to achieving Net Zero carbon emissions across its estate by 2030–2035. To support this ambition, the College appointed a multidisciplinary design team to develop a strategic decarbonisation plan for its city centre campus.
Given the broad age range of the College’s buildings – spanning from the 15th Century to as recently as 2020 – the plan needed to account for a wide variety of construction types, uses, and levels of thermal performance. The estate includes over 30 buildings, many of which are listed (Grade I and Grade II), and serve diverse functions such as student accommodation, teaching spaces, dining facilities, and welfare areas.
CPW were engaged to deliver an extensive building thermal envelope performance study, and building services review, across the estate to develop a comprehensive MEP decarbonisation strategy that could serve as a clear, phased roadmap to net zero.
Respecting history while shaping the future
The built environment of the college is a blend of architectural heritage and academic purpose. Any proposed upgrades had to respect the conservation status of the estate while pushing forward a high-performance, low-carbon future.
Working alongside the College’s appointed Heritage and Masterplan Architects, CPW carried out a detailed survey of each building to assess opportunities for realistic and achievable thermal improvements. These interventions are a fundamental step in reducing heating demand and maximising energy efficiency. The assessment covered elements such as walls, windows, roofs, air leakage, and thermal bridging.
Crucially, each improvement was evaluated for its viability within the heritage context and likelihood of receiving approval from conservation authorities. The resulting strategy balances sensitivity with technical ambition, respecting the past while planning for a sustainable future.
Engineering a low-carbon transition
The CPW team undertook a detailed review of the campus’ primary plant installations, assessing the age, location and condition of heating, hot water and electrical generation infrastructure. CPW then produced a tailored options appraisal for future energy generation – evaluating how on-site, electrically driven low carbon solutions such as heat pumps could replace the current carbon intensive gas-fired system.
The image to the left shows campus’ heat networks.
Three potential pathways for heat generation and delivery were developed, each carefully considered against space availability, operational impact, planning constraints, and carbon performance:
Decentralised air source heat pumps
Creation of two new energy centres
Development of a single centralised energy centre for the full estate
We worked collaboratively with the College and design team to present the benefits and trade-offs of each, using clear visuals such as site-wide plans and comparative matrices. This structured approach enabled the College to make informed decisions that support their sustainability and operational goals.
A fabric first approach
From the outset, the project has followed a fabric-first philosophy, reducing heating demand before introducing new systems. This underpins the transition away from high-carbon, gas-based systems to electrically powered solutions aligned with the decarbonised UK electricity grid.
To support this, CPW used thermal imaging techniques to evaluate insulation performance and identify areas of heat loss across the estate. This was complemented by the deployment of an innovative U-value tool, which enabled more accurate calculations of existing thermal performance and helped target appropriate and viable fabric upgrades across a wide range of building types.
By improving the thermal performance of the estate and integrating low-carbon technologies such as air source heat pumps, the College can significantly reduce energy consumption and carbon emissions while maintaining the integrity of its buildings.
CPW also produced a Heat Decarbonisation Action Plan, outlining the next-stage development works needed to deliver the transition. This was supported by a Proposed Roadmap, a visual timeline mapping out key interventions and the cumulative reduction in carbon emissions between 2022 to 2035 and beyond.
“We engaged CPW to work with us at St John’s College to develop a masterplan for the site. One of our most critical needs was to reduce our carbon consumption. We were really impressed with the approach from CPW.
“Their communication was exceptionally good, and they were able to reduce complex workings into easily understood principles. They participated in stakeholder engagement, with students, staff and with our Governing Body.
“We are currently working with them on the first step of our plan to reduce carbon usage by improving existing fabric performance (which is hard in listed buildings) and then to introduce a centralised renewable energy centre to service our main campus.”
Working in partnership
With a phased delivery expected through to 2035, programme and cost control are vital. CPW continue to monitor both on an ongoing basis, working in close collaboration with the College, consultants, and contractors.
Our approach places equal importance on technical excellence and stakeholder alignment.
We continue to provide expert input to ensure that building services infrastructure meets performance expectations and cost parameters, while enabling long-term decarbonisation and operational resilience.
Targeting Net Zero Carbon by 2030–2035
Over 30 buildings surveyed, including Grade I and II listed properties
Fabric-first approach with conservation-led thermal improvements
Options appraisal for low-carbon heat generation using electrically driven heat pumps
Development of a comprehensive Heat Decarbonisation Action Plan and carbon reduction roadmap
Want to find out how we could support your decarbonisation journey? Visit our services page.