PHAM NEWS | OCTOBER 2025 24 Gas & OilBoilers


Is the market ready for effi ciency drive?


The RDB2.2 BX VC36 Grant oil burner, part of Riello’s series of one stage light oil and kerosene burners


a large technological step change which raises important questions about whether this is the most impactful or cost- eff ective lever to pull in the eff ort to decarbonise off -grid heating. One of the stipulations of the


The heating sector must balance net zero ambitions with an ageing workforce, aff ordability and readiness. While tighter boiler standards target effi ciency, Graham Barker from Riello Burners argues pragmatic approaches such as renewable liquid fuels could achieve fairer and more sustainable progress.


T


here’s no doubt that the UK’s heating engineers are an ageing group, and with


age comes a reluctance to change. This leads to debates over where this leaves our industry and its urgent need for upskilling in digital controls and heat pumps, to name just a couple of areas. The UK’s transition to


net zero demands bold, coordinated action, and the heating sector is rightly a focus. As part of this shift, the Department for Energy Security and Net Zero (DESNZ) has proposed raising product standards for space heating, including a requirement for residential liquid-fi red combination boilers to modulate their heat output down to 30% by mid-2028. While the intent to drive


effi ciency is welcome, this specifi c requirement risks moving faster than the market can reasonably support, creating technical, economic, and practical challenges for manufacturers, installers, and homeowners.


Graham Barker Residential sales director at Riello Burners


Modulation technology The concept of modulation – adjusting boiler output to better match heat demand – is a sound one. It can improve comfort and reduce on/off cycling and is now common practice for gas fi red appliances. However, applying modulation technology to liquid fuel boilers, particularly in a domestic combination format, introduces far more complexity. One point of note is that liquid fuelled boilers generally have a higher water content than the equivalent gas fi red appliance, so they do not require such rapid changes in heat demand as they are able to ‘store’ more water than a low content gas boiler. In addition, the actual


A key approach could be


accelerating the adoption of


renewable liquid fuels


effi ciency gains when modulating oil boilers at low loads, particularly in condensing mode, appear marginal. However, that’s not to say modulation is not viable for residential liquid fuelled boilers, but to introduce modulating technology into such appliances is not as straightforward as it is for gas fi red appliances and requires


DESNZ consultation is that any technology changes should not come at a cost to the consumer. If modulating operation is to become a requirement for all residential liquid fuelled boilers, the unfortunate result will be a large increase in appliance costs, in some cases over 100% increase on current costs for consumers. This is evident with current technology available on the market, which does come at a much higher purchasing price.


Installer readiness There’s also the issue of installer readiness. The heating workforce is already adapting to new technologies like heat pumps, hybrid systems, and smart controls. Introducing complex, niche technologies that require manufacturer- specifi c training and tools could create new access barriers, slow adoption, and stretch training infrastructure beyond capacity. I am an advocate for a


broader, more fl exible approach, one that supports evidence-based policy, aligns with consumer aff ordability, and keeps the UK on track toward net zero. A key part of that approach


could be accelerating the adoption of renewable liquid fuels such as Hydrotreated Vegetable Oil (HVO). HVO off ers up to 88% carbon reduction compared to kerosene, and it has already been successfully trialled in thousands of homes through a self-funded industry programme. Importantly, a modest 20% blend of HVO with existing heating oil could be introduced immediately, delivering meaningful


emissions cuts without requiring new hardware, new training, or taxpayer subsidy. However, it’s important to


acknowledge that renewable fuels are not a silver bullet. Their long-term success depends on sustainably sourced feedstocks, transparent supply chains, and policies that ensure fair access across competing sectors like transport and aviation. Any push to adopt renewable liquid fuels must be matched with rigorous standards and forward-looking infrastructure planning.


Complex road ahead The path to Net Zero will be complex, and it will require more than one solution. For lasting impact, regulation must work hand in hand with industry, refl ect the current capabilities of the market, and pave the way for innovation that is not only technically sound, but commercially viable, socially equitable, and environmentally sustainable. The liquid fuel heating sector


stands ready to innovate. With the right policy signals and a pragmatic, collaborative approach, it can help deliver cleaner, smarter heat to homes across the UK, without leaving anyone behind. ◼ phamnews.co.uk/1025/40


CUT TO THE CHASE


 The government is proposing a 30% boiler modulation requirement by 2028


 Modulation adds complexity, with limited efficiency gains for oil boilers


 Consumer costs could rise over 100% under proposed standards


 Renewable fuels like HVO offer immediate, lower-cost carbon reductions


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