Spotlight on condensing boilers

Energy efficiency has put the focus firmly back on condensing technology as the pragmatic, affordable and highly-effective solution to achieving significant energy and carbon savings from heating. 

It is widely agreed that a combined approach of improved energy efficiency and an increased uptake in renewable energy equipment are key to achieving a more sustainable future. Yet until recently, energy efficiency has been regarded as the Cinderella of energy policies, lacking the more obvious appeal of new renewable technology. Now, supported by the introduction later this year of two new pieces of environmental legislation, energy efficiency is firmly centre stage, and the spotlight is on condensing technology as the pragmatic, economical and effective means of achieving environmental targets and long-term financial savings.

The Energy-related Products Directive (ErP) (EU Directive 2009/125/EC) and the Energy Savings Opportunity Scheme (ESOS) promote higher standardised efficiencies for heating and hot water products and practical, affordable measures designed to help businesses reduce their carbon footprint whilst benefitting from energy cost reductions of around 20 per cent. As heating and hot water generation account for nearly half the total energy use of a building and its associated greenhouse gas (GHG) emissions, raising thermal efficiencies is critical if we are to move the UK to a more sustainable future.

Gas has always been the most popular source of energy in the UK, responsible for around 80 per cent of domestic, commercial and industrial heating. This is due in part to the nation’s high proportion of old buildings, the majority of which have boilers at the heart of the heating system. While new buildings are designed to require less energy for heating, the real challenge lies in improving the efficiency of our existing building stock if we are to achieve our steep carbon reduction target of 80 per cent by 2050.

This leads us to the renewed focus on condensing technology as the practical solution to rapid, substantial energy and carbon savings from heating.

Practical – Retrofitting a condensing boiler is often the only possible option for raising the thermal efficiency of our older buildings. Replacing an inefficient 15-year-old atmospheric boiler operating at just 50 per cent efficiency with a modern, 98 per cent efficient condensing boiler can reduce energy bills by as much as half.

Highly efficient – Condensing technology offers the highest efficiency, as recognised by the ErP which will essentially make it mandatory to install high-efficiency condensing boilers below 400kW on both new build developments and refurbishment projects.

Affordable – Condensing boilers are a cost-effective, replicable option, offering rapid return on investment and the prospect of future savings.

Clean – Today’s clean-burning, fully-modulating condensing boilers provide a greener solution to heating with minimal NOx and carbon emissions, two of the most environmentally harmful of the greenhouse gases.

Tried and trusted – There is no shortage of skills or knowledge when it comes to tried-and-tested condensing boiler technology. Recent reports of discrepancies in the predicted and actual energy use of a building, often as a result of underperforming renewable energy equipment due to insufficient understanding, contrast with condensing boilers which are reliable, easy to install and to maintain.

Flexible design – Modern boilers are designed for greater flexibility. Installation is easier with lighter, more compact boilers supplied on wheels for greater manoeuvrability or able to be disassembled where access is restricted. Multiple boiler installations on cascade systems facilitate wider output modulation to maximise energy and carbon savings while bespoke rig systems can be tailored to accommodate the plant room. Both factory-finished, prefabricated systems offer improved quality control and minimise downtime and labour costs.

Versatile – Central to the ongoing popularity of condensing boilers is the pivotal role they play in both retrofit and new development projects. Condensing boilers can transform the performance of a building in retrofit applications or, equally, operate alongside renewable energy products such as gas absorption heat pumps or biomass boilers, to supply seasonal top up or meet peak demand for low carbon heating. Arguably the most effective retrofit technology available today, it is the bridge to future decarbonising of heat in buildings.

The next step

For businesses facing the dual challenge of meeting increased legislation and achieving greater productivity, gas condensing boilers are an affordable, effective solution to cleaner, greener heating. However, given that the cheapest and cleanest energy choice of all is not to waste it, we should not rest on our laurels.

Even a high efficiency condensing boiler will waste at least 10 per cent of the energy input up the flue when operating at full load and high temperatures (82/71°C flow and return). This is acknowledged in the ErP where the heating efficiency for boilers between 70 and 400 kW is set at 94 per cent GCV at 30 per cent load and dropped to 86 per cent at 100 per cent load. The headline efficiency figures of a boiler represent the maximum efficiency it can achieve in idealised conditions, typically at half load and low temperatures; on an existing LTHW system, generally sized on high flow and return temperatures, the boiler will be prevented from fully condensing.

For this reason, heating manufacturers must continue to innovate to offer condensing boilers that achieve maximum, full time combustion efficiency even on older heating systems.

Full-time condensing boilers that use heat recovery technology to lift the efficiency of the boiler a further 10 to 15 per cent, even at high flow and return temperatures, represent the next stage in condensing technology and the perfect retrofit solution. By recovering otherwise wasted energy and passing it back into the system for the benefit of cold water pre-heat or space heating, they use the energy input more effectively and sustainably to deliver still greater energy and carbon savings with the same rapid return on investment. Full-time condensing boilers epitomise the ongoing appeal of condensing technology to businesses as a practical means of helping protect UK energy security, achieve a lower carbon footprint and reduce operating costs, now and in the future. For this reason, it is no surprise that condensing technology is back in the spotlight as a win-win solution to improved energy efficiency.

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