Low carbon retrofits: Reducing emissions across our estate

As part of the University’s commitments to reduce our overall carbon emissions, specifically our commitment to reducing energy-related emissions from our operational estate to absolute zero carbon by no later than 2048, we are transforming how our buildings use energy.  

Over the last few years, we have been investing in low-carbon retrofits of our existing buildings. These upgrades focus on reducing energy use and replacing fossil fuel systems with cleaner, more efficient technologies. 

Expanding renewable energy with solar power 

Photovoltaic (PV) panels, also known as solar panels, have now been retrofitted to the roofs of several University buildings to generate clean electricity. In 2022, PV panels were fitted to the Entopia Building and now produce over 10,000 kWh of electricity per year, meeting around 7.5% of the building’s total energy needs. 

A more extensive installation followed in 2023 at the William Gates Building, where 1,500 m² of PV panels generated 248,000 kWh of electricity in the first year of operation. This project was funded by the University’s Carbon Reduction Fund. 

While solar panels do increase renewable energy generation capacity and are known to offer a good return on investment, their contribution to carbon reduction is now more limited due to the rapid decarbonisation of the UK’s electricity grid. Greater carbon savings are now found in addressing how we heat our buildings. 

Heat pump projects supporting emission cuts 

Switching from fossil fuel gas-fired heating systems to efficient electric heat pumps, especially when combined with fabric upgrades (improvements to the building’s physical structure to reduce heat demand), delivers a substantial reduction in building-related emissions.  

Several such retrofits have been completed or are currently underway: 

• Entopia Building (2022): A ‘fabric first’ retrofit addressing the building’s physical structure greatly reduced heat losses, allowing most of the building’s heating to be provided by just 60 kW of heat pump capacity. 

• Keynes House (2024): Two 75 kW air source heat pumps replaced old gas boilers emitting around 28 tonnes of CO₂ per year (tCO₂/yr), supported by Government funding. It is often difficult to find space for large heat pumps, but in this case, the solution of replacing 90-year-old windows with triple glazing allowed for enough reduction in peak heat demand that smaller heat pumps were sufficient. 

• Donald McIntyre Building (2025-): Home of the Faculty of Education, an ambitious project is underway to replace ageing gas boilers emitting around 120 tCO₂/yr with four 90 kW air source heat pumps. The project required upgrading the nearby electrical substation (facility that reduces high-voltage electricity to usable levels and distributes to buildings) and replacement of building radiators with larger units that have lower surface temperatures, improving the efficiency of the heat pumps further. 

• Hutchinson Building (2025-): The future home of the Li Ka Shing Early Cancer Institute is undergoing the most impactful retrofit for carbon saving to date, including the ventilation system being upgraded with heat recovery technology, allowing heat from outgoing air to be reused. This will significantly reduce heating demand, allowing the replacement of gas boilers and chillers with reversible air source heat pumps that can provide heating as well as the cooling required for research purposes. The gas boilers were emitting around 320 tCO₂/yr. 

These projects demonstrate how targeted investment in existing buildings can support both our sustainability commitments and modern building performance, ensuring we continue to reduce carbon emissions while meeting the diverse needs of our University community. 

Looking ahead to future carbon reduction 

A recent study considered opportunities for installing additional PV panels across the estate. Potential installations of these panels will be considered where they offer a reasonable return on investment.  

The University is continuing to seek further opportunities to replace high carbon gas boilers with low carbon heat pumps associated with the Reshaping the Estate and ongoing maintenance programmes. 

More information is available on our Carbon and energy and Our progress page.