Modern Building Services

8 MODERN BUILDING SERVICES MARCH 2022 HEATING I n just three months’ time, tighter water heater efficiency standards will effectively remove the opportunity to carry out like-for-like non- condensing water heater replacements in the vast majority of non-domestic buildings. How can building services professionals ensure that businesses are protected moving forward? Our advice is to encourage proactive planning now to future proof the hot water system. Stricter efficiency standards Back in December, the government published its much-anticipated changes to Building Regulations. Five revised Approved Documents were unveiled in total, including Approved Document L which is concerned with the conservation of fuel and power in existing non-domestic buildings. One of the uplifts within the document relates to tighter minimum thermal efficiencies for dedicated domestic hot water heaters. The new requirements require direct-fired water heaters to achieve aminimumheat generator seasonal efficiency of 91% (GCV) for natural gas and 92% (GCV) for liquefied petroleumgas (LPG). For indirect- fired water heaters, theminimum heat generator seasonal efficiency is set at aminimum seasonal efficiency of 91% (GCV) for both natural gas and LPG. The new standards, which will apply to both existing and new non-domestic building stock, will come into force from 15 June 2022. What does this mean in practice? In essence, the more stringent efficiency standards will phase out the use of non- condensing water heaters in the vast majority of buildings. Are there any exclusions? Approved Document L notes that in very exceptional circumstances, where condensing water heater replacement is deemed not suitable or practical by the Building Control Body, a minimum seasonal efficiency of 80% for gas, or 79% for LPG may be used. Condensing vs non-condensing Direct-fired water heaters are well established as providing an efficient, cost-effective means of delivering large volumes of sanitary hot water in a short time. Hospitals, hotels and leisure centres are just some of the organisations with a high demand for instantaneous hot water that rely on direct-fired water heaters to meet their requirements. Currently, mostmanufacturers and suppliers offer a choice of condensing and non-condensingmodels. Condensing water heaters, unlike non-condensing varieties, can capture and re-use latent heat that is otherwise lost through the flue. As a result, they are up to 20% more efficient than non-condensing models. Units like the Andrews Water Heaters ECOflo, MAXXflo EVO and SUPAflo EVO, for example, can achieve near maximum efficiencies of up of 98%. NOx emissions are also lower, making them the natural, sustainable choice in new build premises. But a significant number of businesses still rely on non- condensing water heaters to provide hot water services. What’s more, at present, there is still the option to carry out like-for-like replacements of non-condensing water heaters. The advantage of this rapid, easy-fit approach is that no major work is involved, so the equipment can be replaced quickly with minimal disruption to the daily operation of the building. The disadvantage is that some businesses consequently fail to upgrade to the more efficient technology and so miss out on the energy, cost and emission- reduction benefits from the more energy-efficient equipment. Hence the government’s stick to rule out non-condensing water heaters. Introducing more stringent minimum efficiency standards is part of its roadmap to drive improved efficiency in buildings and achieve a net zero economy by 2050. Additional planning Given that water is a critical service, what will the changes mean in practice for businesses and organisations? While the benefits of switching to more energy efficient technology are clear, certain factors will require additional planning. Take the flueing arrangement. A traditional non-condensing water heater will typically require a vertical flue that will go from the plantroom through the roof. Subject to installation standards and requirements, there may be the option to line the existing flue rise when replacing a non- condensing unit with a condensing water heater. ➜ Changes to Part L of Building Regulations are set to rule out non-condensing water heater replacements from 15 June this year in favour of more energy-efficient condensing units. Baxi’s Technical Director Andy Green looks at the implications for Building Services professionals and why it pays to plan ahead Start planning now for Part L changes FEATURE HEATING