Beyond Net Zero: Saying goodbye to gas

Significantly reducing the operational energy use and CO₂ emissions of their buildings or estates is an increasingly urgent priority for most organisations, both to meet net zero carbon targets and to reduce operational costs. This means removing fossil fuels from existing buildings now. Less than 1% of existing building stock is replaced annually, and most buildings aren’t candidates for extensive retrofit in the short term. As a result, we believe that delivering decarbonisation quickly and affordably is the biggest challenge to achieving net zero in the built environment in the limited time we have to reduce the severity of impacts of global heating.

At Max Fordham we are pioneering the decarbonisation of existing building stock through tightly focused, engineering-led projects. At Wolfson College, University of Oxford, we helped secure public sector grant funding (via Salix) to decarbonise their estate within an exceptionally demanding timeline. We analysed heating demands and existing systems, then designed bespoke solutions that could be delivered in practical and achievable steps.

Many of our clients have declared climate emergencies and set ambitious targets for reducing operational carbon emissions Across multiple projects we have honed our approach to turn their intention to decarbonise into action.

We retain existing infrastructure (pipework, plant rooms, controls, sometimes radiators) as far as practically possible, often aligning future upgrades with a building’s existing maintenance plan. This has the added benefit of minimising embodied carbon emissions, something we increasingly factor into our approach. 

We won’t take a building out of action unless it’s totally unavoidable, because this can be impractical and prohibitively expensive. Fabric upgrades to reduce energy demand are rigorously examined to ensure they are worth the potential cost and disruption. In practice this means only the most impactful measures are taken, such as replacing single glazing or installing limited insulation. When working on heritage buildings, we do what’s possible within the sensitive context. In short, decarbonisation means working with what you have and weaving decarbonisation into the ongoing process of renewal and upgrade that all buildings need to remain fit for purpose.

Most gas boilers will be replaced with air source heat pumps (ASHPs). There are some challenges when implementing ASHPs, but these can be mitigated through good design and optimisation.

At Wolfson College, we designed an innovative large-scale heat pump utilising carbon dioxide as the refrigerant. This design allowed us to fit the heat pump into the available space and produce the higher flow temperatures required to retain the existing heat distribution system. At Linacre College, also at the 
University of Oxford, we designed an entirely different system that utilised multiple domestic units. These are quiet and flexible to configure, so could fit into a series of small, acoustically sensitive areas. 

Replacing gas with ASHPs is a form of electrification. The Coefficient of Performance (COP) of a heat pump measures the ratio of useful heat output to electrical energy input. A higher COP means the heat pump delivers more heat for the same amount of electricity used. We ensure that systems reach their full potential through post occupancy evaluation and optimisation across varying seasons and building usage conditions.