Edmund Vaughan, chapmanbdsp’s Design Group Director, argues that with programmes stretching up to two and a half years, owners must start electrifying now – using heat pumps, thermal storage and smart phasing despite lingering EPC B uncertainty.
Building owners have varied motivations for reducing reliance on fossil fuels through electrification. With the UK grid decarbonising, electricity presents the largest operational opportunity: replacing gas-based heating with electric alternatives such as heat pumps, often while retaining the existing building fabric and tenants in situ.
Successful delivery starts with understanding priorities, leasing arrangements, budget and time constraints, then establishing a clear roadmap. Technical work typically includes integrating heat pumps into existing systems and optimising roof plant space.
There are challenges in both implementation and legislation. An industry-wide frustration is the lack of clarity around requirements for buildings to achieve EPC B, previously signalled for 2030. This uncertainty is delaying preparations, even though EPC modelling favours all-electric buildings because carbon factors reflect the decarbonised grid. Electrification is therefore a key lever, alongside demand-reduction measures such as lighting upgrades and fan efficiencies.
Risks and constraints are best surfaced at the feasibility stage. A first step is a feasibility strategy with an initial client meeting and site visit to review existing power provision, particularly where gas-based heating and hot-water systems are in use. This is also the point to define priorities such as phasing, treatment of costs within service charges, and planning risks. A clear understanding of leasing arrangements and tenant-retention priorities – whether the building is live (occupied) or vacant – should inform the study. Options can then be evaluated against these variables.
Technical integration requires careful load balancing. Heat pumps operate at lower temperatures than gas boilers, which affects compatibility and business continuity. Options include two-stage systems. Fan coil units and other emitters should be assessed to determine whether lower flow temperatures materially reduce heating output. Coordination with manufacturers helps confirm performance at revised temperatures.
Electrification projects often need space reconfiguration. Gas boilers typically sit in basements or on roofs. In many ‘wedding-cake’ buildings with shrinking upper floorplates, roof plant space is at a premium. The task is to use available space without affecting lettable areas.
Thermal storage can address peak sizing. Design heating conditions reflect infrequent extremes. Stores charged off-peak can discharge at peak, boosting capacity without oversizing the heat pump plant. Thermal stores can be located within the building, reducing roof space needs.
Combined air-source heat pumps that provide both heating and cooling support a holistic approach. By replacing chillers, they can reduce roof plant area and enable heat recovery between heating and cooling systems.
In a recent City of London project, conversion from gas to electric replaced roof cooling towers and selected chillers with air-source heat pumps that now provide both heating and cooling.
Complexity – especially with in-occupation works – extends programme length. Allow up to two and a half years. Seasonal changeovers, phased works to limit tenant disruption, and supply-chain issues also affect duration.
Progress should be checked against the feasibility strategy through regular EPC and thermal analyses to prevent scope drift and keep sustainability goals central. Engagement and clear communication with tenants are as important as the technical delivery.
In summary, legislative uncertainty should not delay decarbonisation planning. Given typical electrification timelines of up to two and a half years, the time to plan is now. Electrification will remain a growth area across the sector, providing roadmaps to a more sustainable and compliant future.
