Chris Caton, Product Director – Commercial, Ideal Commercial Heating
In a perfect world, every commercial building could immediately transition to a low carbon electric heating solution. However, existing buildings present a set of challenges that means decarbonisation is a journey, not a single event. Hybrid systems provide an effective bridge on that journey, allowing energy managers to make meaningful carbon reductions while working within the practical limitations of their buildings.
What is a hybrid heating system?
Hybrid heating systems combine heat pumps as the lead source with a complementary heat source supporting peak demand or extreme operating conditions, most commonly high-efficiency gas boilers.
The two most common configurations for hybrid heating systems are bivalent and parallel.
In a bivalent arrangement, one heat source replaces another at a defined temperature or load threshold. This typically sees the heat pump covering the base load with boilers taking over during peak demand.
In a parallel configuration, the heat pump operates to deliver as much heat as possible within its optimal performance range. Boilers operate alongside the heat pump during peak demand periods or when higher temperatures are required.
Can all commercial buildings use heat pumps?
There is understandable enthusiasm around heat pumps, and rightly so, yet not every building can be served by heat pumps alone.
Many commercial buildings were never designed for low temperature heating (heat pumps operate at a maximum flow temperature of 55°C, whereas commercial gas boilers typically operate at a flow temperature of 70°C to 80°C). Their existing radiators, fan coil units, air handling units, heat interface units, underfloor heating, pipework and controls often rely upon traditional higher operating temperatures that can be difficult and expensive to modify.
Electrical infrastructure presents another significant challenge. Many sites simply do not have sufficient incoming electrical capacity to support a full heat pump installation without substantial upgrades. These upgrades can introduce considerable cost, lengthy timescales and disruption to building occupants.
Then there’s the space issue. Traditional plant rooms are internal, but heat pumps require external space, careful consideration of airflow and appropriate acoustic design. Not every site can accommodate these requirements easily.
In these situations, hybrid systems allow us to introduce heat pumps as part of the solution, whilst recognising on-the-ground constraints.
Can domestic hot water run off a low carbon system?
Domestic hot water is often one of the most challenging aspects of commercial heating decarbonisation.
Space heating and hot water have very different operating requirements. Heat pumps perform most efficiently when delivering relatively low flow temperatures. Domestic hot water, however, demands significantly higher storage and distribution temperatures to satisfy both user expectations and hygiene requirements. Attempting to satisfy both demands from a single heat source can lead to compromises in efficiency.
For this reason, we’re increasingly seeing decoupled solutions become the preferred design strategy, with dedicated domestic hot water generation, whether through dedicated air source heat pumps, standalone cylinder systems or highly efficient gas-fired water heaters.
What are the financial implications of decarbonisation?
Perhaps the greatest advantage of hybrid systems is that they allow decarbonisation to happen progressively.
Few organisations have unlimited capital budgets and replacing an entire heating system in one project is not always feasible. Hybrid systems allow organisations to install heat pumps alongside existing or replacement condensing boilers, reducing emissions immediately while spreading investment over several years. This phased approach also reduces operational risk.
As energy managers, you can evaluate actual heating demand, monitor system performance and develop future investment strategies based on real operational data rather than assumptions.
It also prevents unnecessary oversizing of heat pumps, helping to optimise both capital expenditure and long-term operating costs.
Most importantly, it enables meaningful progress today rather than delaying projects while waiting for ideal conditions that may still be several years away.
Supporting the transition to net zero
There is no question that heat pumps will play a central role in the future of sustainable commercial heating. However, achieving net zero is not simply about replacing every boiler with a heat pump. For many existing commercial buildings, hybrid heating systems represent a practical solution on the road to decarbonisation. They allow us to put the right technology, in the right building, at the right time.
To find out more about this subject, book Ideal Commercial Heating’s CIBSE-approved ‘Low carbon hybrid heating system considerations’ CPD at idealcommercialboilers.com/cpd-courses.
This article appeared in the September 2026 issue of Energy Manager magazine. Subscribe here.
