Chris Caton, product director – commercial, Hamworthy Heating, looks into his crystal ball.

“The only certainty is that nothing is certain”; so wrote Roman author Pliny the Elder some 2,000 years ago. How apt that phrase seems in today’s world when facing the reality of climate change. The drive to Net Zero by 2050, whereby the UK reaches net zero greenhouse gas emissions, requires the transition from a reliance on fossil fuels to clean, ‘green’ energy and technologies, but precisely what those energy sources are, and the mix of technologies to deliver them, remain uncertain.

An integral part of the Net Zero path is the decarbonisation of our buildings. The construction and operation of buildings is responsible for around 38% of global carbon emissions, and heating and hot water make a significant contribution to that. In the commercial sector, we have already seen a gradual move away from gas boiler specification in the new build sector. In the design phases of a new non domestic building heat pumps are the leading alternative or technology of choice, but the roadmap to decarbonised heating across all building types is not at all clear, with many policy level decisions yet to be made. So, what will the plant room of the future look like? Whilst we can’t predict the future, we can look at the impact of government decisions and the credible options for future commercial plant rooms.

What is the future?

Firstly, let’s define ‘the future’ in a meaningful, useful way, setting science fiction firmly aside!

Not forgetting the government’s drive to encourage the installation of 600,000 heat pumps (both domestic and commercial) by 2028, which is already in place, there are key dates that will impact the future course of heating in the UK; the first major date being 2026. In 2026, the government is set to make a final decision on the use of hydrogen for heating in buildings, following hydrogen heating trials, including a neighbourhood trial and village-scale trial, along with plans for a possible hydrogen town that could be converted before the end of the decade. The trials are designed to assess the feasibility, safety, consumer experience and other costs and benefits of hydrogen for heating buildings. The 2026 decision date will have a major impact on the future of heating in the UK which of course impacts the commercial plant room.

So, 2026 is an important year, but it hardly feels like ‘the future’, does it, when the date is just around the corner? The plant room in 2026 will look pretty much identical to the plant room of 2023. If that is the case, then when can we expect to see genuine changes in commercial plant rooms?

I think there's one constant in all of this uncertainty, which is 2035. This date is significant, as an interim Net Zero target has been established for 2035 to reduce emissions in the UK by 78% compared to 1990 levels. It’s also the date set for all new heating systems to be Net Zero compatible. In other words, no new gas boilers will be manufactured or installed, but plant rooms with existing operational gas boilers can continue to utilise them.

Well, that was the plan at least, but the recent Standards and Efficiency Consultation puts a question mark over this. Section one of the consultation surprisingly addresses improving natural gas fired boiler efficiency from the typical 5:1, to 10:1. This consolidation is for all boiler types up to 45kW and proposes these changes apply up to 70kW. To achieve this a significant jump in modulation is necessary that would require a big R&D investment from boiler manufacturers, which was entirely unexpected in light of the 2035 announcement. It is just a consultation, but it adds uncertainty to one aspect we thought was certain.

Having set 2035 as the date we are focussing on, I should raise one little caveat in the form of the ‘MISSION ZERO Independent Review of Net Zero’ report produced by Chris Skidmore MP. This review recommends bringing the date forward to 2033. Like I said, these are uncertain times!

The 2035 plant room

When it comes to new buildings, I think the 2035 plant room is relatively straightforward to predict as it must comply with Building Regulations or, as it will be post 2025, Future Buildings Standard. This means a thermally efficient building with a low carbon-based heating system, maybe with additional renewables such as solar panels contributing to the running of the heat pump.

The heat pump itself will probably look very similar to current ones, but I would expect latest models to be delivering higher temperatures than are currently achievable where domestic hot water is needed. One of the main changes I foresee is the choice of refrigerants, with a move away from those that are harmful to the environment to those that have a lower Global Warming Potential (GWP). Ultimately, that means natural refrigerants such as propane with a GWP of four, or carbon dioxide which has a GWP of just one. Natural refrigerants are harder to work with and will require changes to heat pump systems, and a more carful integration in to the building, managing return temperatures, but they have to be the way forward.

Whilst the 2035 heat pump will probably visually look very similar to those we have today, the heating system fed by the heat pump should look a little different. That’s because accurate system sizing is very important to get the most energy efficiency from the heat pump. The Approved Document L uplift requires all new and replacement heating systems to be designed with a maximum flow temperature requirement of 55°C. This means bigger radiators are required to get that energy into the room, operating on that temperature. As an industry, we are notoriously poor at sizing heating systems accurately and, more often than not, allow aesthetics to dictate the size of a radiator.

When we move away from new build to look at a refurbished commercial plant room, here the picture is a little different. As we all know, the majority of older properties have comparably poor thermal efficiency and to improve the thermal properties involves a whole host of expensive, disruptive work to the building. But without that work, relying solely on a heat pump which has a maximum flow temperature of 55°C is unlikely to provide the level of comfort required. Furthermore, the cost to run a heat pump in this way would also be very high. Here, expect to see hybrid systems which do indeed include a heat pump as the main heating source, but with the existing gas boilers retained (or maybe new hydrogen boilers!) to provide supplementary heat when required. This hybrid solution is a compromise, but it does reduce a building’s carbon footprint without a huge spend and quickly.

Looking further ahead: hydrogen

Taking into account a typical commercial boiler lifespan, by 2035 any current gas boilers in place are likely to need replacing and their replacements must be Net Zero compatible. So that means no new natural gas boilers. Heat pumps are readily available, but what about hydrogen boilers? By 2050, will the hydrogen powered boiler be a staple of plant rooms?

Clearly that depends on the government’s decision in 2026. If the decision is made against hydrogen, then it’s heat pumps all the way along with, maybe, electric heating. If the decision goes the other way, and hydrogen is going to play a part in heating in the future, then we have a quite different scenario, where gas boilers are more than likely to continue to form part of the heating mix as 100% hydrogen fuelled boilers simply don’t exist; no manufacturer has gone beyond a prototype and those are for domestic boilers only. The amount of innovation and R&D involved in producing a boiler that can operate on natural gas like today, but then can be converted at some point to 100% hydrogen, is enormous and, ultimately, years away. Hydrogen has very different properties to that of natural gas.

A switch to hydrogen is likely to be done on a regional basis as infrastructure is rolled out. It might even only be deployed as a rural rather than mainstream solution, replacing LPG. Furthermore, let’s not forget that’s it’s not just boilers that use the gas grid. In addition, appliances such as hobs, ovens and fireplaces would all need to be developed to specifically run on hydrogen.

The use of hydrogen in heating buildings remains the most uncertain part of all. I’m not even sure the decision in 2026 will be definitive – it could be postponed.

Diversification

There’s only one thing we can be certain of in this uncertain decarbonised heating future, and that’s diversification. The commercial plant room of the future will feature a mix of technologies to satisfy the heating requirements of different building types, old and new, and to make best use of energy prices. I’m going to stick my head out and say that hydrogen will form part of that mix and will replace natural gas along with the other key heating technology which will undoubtedly be heat pumps. But there may well also be direct electric heating in the mix, and that could be through immersion heaters, or it could be electric boilers, or it could be panel heaters. The plant room of the future is unlikely to rely on a single heating method but will feature a combination of these to deliver energy efficient, decarbonised heating in an intelligent way to minimise operating costs.