PHAM NEWS | MAY 2026 28 Hybrid HeatingSystems


primary energy and delivered energy metrics. The growing emphasis on actual energy performance, rather than purely notional design targets, further strengthens the case for systems capable of optimising energy use in real time. Importantly, hybrid systems


integrate eff ectively with complementary measures such as solar PV, improved fabric performance and, where applicable, connection to low- carbon heat networks. For designers and specifi ers, this creates opportunities to develop holistic solutions that meet both regulatory requirements and operational needs.


Pragmatic pathway


The decarbonisation of existing commercial buildings presents a number of challenges, but hybrid solutions could provide a practical and fl exible way to deliver on carbon reduction commitments, says Steve McConnell.


T


he recently announced Future Homes and Buildings Standard (FHBS) signals a decisive


shift toward low-carbon heat, electrifi cation and higher energy performance expectations. For heating engineers and consultants, the question is no longer whether systems in new-build properties must decarbonise, but how to do so in a way that is technically viable, economically deliverable and aligned with operational realities. Hybrid heating systems,


which combine heat pumps with gas-fi red boilers, off er a compelling and pragmatic solution. While this approach has historically been viewed cautiously by policymakers, real-world design experience increasingly demonstrates that hybrid strategies can bridge the gap between ambition and practicality, particularly in existing buildings where constraints are most acute.


Retrofi t constraints Heat pumps are widely recognised as a cornerstone of low-carbon heating strategies. However, their application in non-domestic retrofi t scenarios is often constrained by the characteristics of existing buildings and systems.


Many commercial buildings


were designed around high- temperature heat distribution, typically operating at fl ow temperatures of 70-80°C. These systems are frequently paired with emitters, such as radiators or air handling units, sized accordingly. Retrofi tting such systems to operate effi ciently with low-temperature heat pumps (typically 35-55°C) can require extensive and disruptive modifi cations, including emitter replacement, pipework upgrades and, in some cases, improvements to the building fabric. Peak heat loads present an


additional barrier. In sectors such as healthcare, hospitality and manufacturing, demand profi les can be both high and variable. Designing a heat pump system to meet these peaks often leads to signifi cant capital expenditure, plant space constraints and, critically, limitations in available electrical infrastructure. For many organisations,


particularly those in general industry where energy costs directly aff ect competitiveness, these factors can make full electrifi cation diffi cult to justify in the short term.


Best of both Hybrid heating systems address these challenges by combining the strengths of both technologies.


In a typical confi guration, a heat pump is sized to meet the building’s base heating load, operating for extended periods at high effi ciency. A gas-fi red boiler supplements this by meeting peak demand or delivering higher fl ow temperatures when required. This approach off ers several key


advantages: • Optimised effi ciency: By


focusing on base load provision, the heat pump can operate at lower temperatures and higher coeffi cients of performance, maximising both energy effi ciency and carbon savings.


• Reduced capital costs: Smaller


heat pump installations require less upfront investment and are easier to accommodate within existing plant space constraints.


• Minimal disruption:


Retention of existing distribution systems and emitters avoids costly and disruptive internal modifi cations, which is an important consideration for occupied buildings.


• Operational resilience: Dual


heat sources provide redundancy and fl exibility, improving system reliability and business continuity. For energy managers, the


real value lies in control. Modern hybrid systems can respond dynamically to external temperatures, energy tariff s and grid carbon intensity.


Advanced control strategies enable prioritisation of heat pump operation when electricity is both low-carbon and cost-eff ective, while seamlessly switching to boilers during peak tariff periods or when higher temperatures are necessary.


Regulation compliance The FHBS introduces a more stringent compliance framework, particularly for new buildings, while retaining familiar performance metrics such as the Target Emissions Rate (TER) and Target Primary Energy Rate (TPER). Although the policy direction clearly favours electrifi cation and on-site renewables, it also allows for fl exibility in how compliance is achieved. This is where hybrid systems


can play a strategic role. By balancing electrical and gas inputs, hybrid confi gurations can be modelled to deliver favourable outcomes across emissions,


Steve McConnell Director of ICOM


Carbon reduction By enabling faster deployment of heat pumps across the existing building stock, hybrids can accelerate emissions reductions. As the UK electricity grid continues to decarbonise, the carbon intensity of heat pump operation will fall further, enhancing the environmental performance of hybrid systems over time. At the same time, the continued


use of gas infrastructure within hybrid systems provides a pathway to incorporate emerging low- and zero-carbon gases, including hydrogen and biomethane. This future- proofs installations and aligns with broader strategies for decarbonising the gas network.


Grid fl exibility From a grid perspective, hybrid systems off er fl exibility. By shifting demand between electricity and gas, they can help manage peak loads and reduce strain on electrical infrastructure, which is an increasingly important consideration as electrifi cation accelerates. The transition to net zero in


non-domestic buildings will not be delivered through a single technology pathway. While electrifi cation is central to long- term strategy, the realities of the UK’s existing building stock demand fl exible, scalable and pragmatic approaches. Hybrid heating systems


provide exactly that. They enable immediate carbon reductions, align with emerging regulatory expectations and off er a practical route for organisations seeking to balance sustainability goals with cost and operational constraints. In a sector where decisions have direct implications for both environmental impact and business performance, hybrid systems represent a highly eff ective step forward. ◼ phamnews.co.uk/526/38


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