BOILERS & BURNERS


Do gas boilers


still trump heat


pumps?


The fuel-saving efficiency of well-designed gas boilers shouldn’t be underestimated, argues Jonathan Grist. A heat pump might not always be a viable option and a modern gas boiler system can still help to reduce a building’s carbon emissions and energy use.


Jonathan Grist www.viessmann.co.uk


Head of commercial sales Viessmann


I


t’s no secret that gas boilers are not in vogue these days. With government grants, planning policies, public pressure and a desire to do the ‘right thing’ all steering public and private sector organisations towards renewable heating technologies like heat pumps, fitting a fossil-fuel combustion system can feel like a missed opportunity. But should gas boilers really be viewed as the option of last resort? There’s no denying that, on paper at


least, heat pumps can be three to five times more efficient than traditional boilers. However, in reality, this is dependent on numerous factors that vary considerably between products, installations and seasons. Meanwhile, boiler technology has


moved on a lot in the past 20 years. Upgrading to a modern, A-rated, gas-powered system can still reduce a building’s energy use by 20-50% as well as slashing NOx emissions by up to 95%. When Omnia Plumbing & Heating recently replaced a 30-year old gas boiler system at the iconic Bredbury Hall Hotel in Greater Manchester with a cascade of four Vitodens 200-W gas condensing boilers rated at 99kW each, energy consumption went down by an impressive 43%. The high price of electricity


compared to gas can often make efficient gas boilers the most


EIBI | NOVEMBER � DECEMBER 2024


cost-effective solution, too. This is particularly true in the case of retrofits, where an elderly appliance can simply be exchanged for an up-to-date model like for like, without the need for expensive or disruptive upgrades to pipework or building insulation. And, as heat pumps consume


considerably more electricity than boilers, unless you can pay a premium for a green energy tariff or install your own renewable power generation and storage systems, it could be that a heat pump will not significantly reduce your carbon footprint in real terms. Furthermore, in older buildings and situations where space is limited, plus certain commercial and manufacturing applications requiring high water temperatures, heat pumps may just not be viable at all. As a manufacturer with a wide range


of products spanning renewable and combustion technologies, we’re well- placed to assess the various pros and cons of different energy approaches somewhat dispassionately. Our aim is to specify the best solution for the customer. In many cases that still means gas boilers. Indeed, Viessmann continues to invest in engineering ever-better commercial boilers – such as this summer’s launch of the new Vitocrossal 200 CI3 – because we understand the technology’s enduring validity.


What to look for So, if you’re specifying a modern gas-powered heating and DHW system, what types of approaches and components will offer maximum performance and efficiency? At the heart of any boiler is the heat exchanger, so it’s crucial this


is well designed and engineered for longevity and low maintenance. Make sure it’s made of stainless steel, not aluminium. While the latter is lighter and cheaper, it’s susceptible to corrosion. Given a regularly serviced boiler could have a service life of over 25 years, you want the core components to be built to last. Make sure, too, that the burner has the modulation range you need. Gone are the days when boilers were either on or off; now you can accurately match your building’s fluctuating load requirements for optimum fuel efficiency. A range of 1:5 will enable the system to run at 20% of its maximum capacity. The Vitocrossal 200 CI3 has a particularly wide modulation range of 1:10, meaning it can operate at just 10%. It also has two return connections as standard, so that there can be low- and high- temperature circuits if desired, with a lower temperature return for better condensation. Another recent efficiency


innovation is Viessmann’s patented intelligent combustion control technology, Lambda Pro Plus, which ensures consistently high efficiency and clean combustion. It uses a self- calibrating O2 sensor to automatically adjust the burner to match different types and qualities of gas, so E, LL or LPG, as well as up to 20% hydrogen, can all be used without conversion. It also makes for extremely quiet operation and means flue gas inspection intervals are extended to three years, saving time and money. The ease with which you can


integrate your boiler with other building management systems and operate and monitor it remotely are


Viessmann continues to invest in engineering ever-better commercial boilers – the recent launch of the Vitocrossal 200 CI3 is a case in point


also key considerations. You need a user-friendly platform that enables you to commission new heating systems, find spare parts, adjust operating parameters and detect faults. A really good management system will allow you to fix certain issues remotely and quickly, and/ or prevent problems before they even arise, ensuring continuity of service and keeping repair and running costs down. While valuable for any installation, this is particularly essential for total-care organisations like hospitals and care homes.


Space restrictions In reality, you may find your product short list is just that – short – because space and accessibility constraints may rule out many options. If your plant room is small or hard to reach, for example in a basement, compact, wall-hung, pre-assembled modules can be much easier to fit into tight spaces and manoeuvre into position than large floor-standing appliances (or indeed the indoor unit of a heat pump). Similarly, appliances with all components accessible from the front are much quicker and easier to service in confined areas.


When all is said and done, a new heating system is a major investment. You should take time to explore all potential approaches and products, discussing your requirements with a consultant or installer that has expertise across all types of technologies and energy sources. It’s possible that gas may be right for you. ■


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