IN FOCUS The Pitfalls Of Decentralising Electric Water Heating C


entralised hot water systems have been in use in commercial buildings for generations, where the pumped secondary returns ensure hot water is available at the tap quickly. But secondary pipework does lose energy, and this is being cited as a reason to specify point-of-use (POU)


electric water heating in buildings without a gas connection to decentralise the hot water system. The Department for Education (DfE), for example, currently recommends a variety of approaches


to water heating, with centralised systems for catering functions which represent a large, individual demand of hot water. In addition, “design and installation shall prioritise the use of local non-storage (or low storage) ‘point-of-use’ electric water heaters. This is to reduce standing losses from centralised systems and to prevent pipework heat loss, increasing the risk of overheating.” This approach is driving the specification of heat pumps to support the ‘centralised’ kitchen and then


large numbers of POU electric water heaters. A recent example of a primary school with 350 students intended to incorporate more than 35 POU heaters for washbasins located throughout the school. But is this the right way to use the technology? Under BS 5422:2023, the minimum level thickness of insulation is established for non-domestic hot


water service areas to control heat loss (25-40mm for 17 to 60mm external diameter pipework). Under this regulation, where an average of 9W/m maximum heat loss is permissible, secondary losses from centralised systems meet acceptable levels. Under this current condition, if we were to apply the maximum permissible heat loss to a 50m run


of secondary return pipework, operating for 16 hours per day, the secondary losses would amount to 7.2 kWh/day. POU aims to replace the centralised system and eliminate this secondary loss. As a conservative response, we could propose a replacement POU application employing 10 x 15-litre over- or under-sink units. However, you must remember that POU also exhibit standing losses, which can easily be 0.85 kWh/day. Multiply this by the specified 10 units, and losses from POU will equate to 8.5 kWh/day. These are averages, so there will be variance. Overall, the energy losses of both systems are going to be similar. So energy losses are part of both centralised and POU-based systems, and are acceptable within the specification. So are there other considerations? Although units are individually low-cost, at these numbers, the capital investment starts to climb, especially when factoring in the high cost of cabling in each unit. POU electric water heaters are also basic, with no connection to the Building Management System (BMS), so there is no option to highlight a fault, enable the unit or apply time control. That’s compounded by a lack of individual miniature circuit breakers (MCBs) to prevent damage or potential fire from an overload or short circuit. Crucially for water heating, which is a business-critical service, there is no redundancy with a POU water heater. If it breaks, there is no hot water at the tap until it is repaired or replaced. Regular maintenance of hot water systems is a critical part of efficient operation, with regular


replacement of anodes and descaling of tanks where high-intensity temperatures created by electric immersions encourage the formation of limescale. This is wet, dirty work that, in centralised systems, is contained within the plant room. While the issues of limescale can be virtually eliminated in centralised systems such as Adveco’s award-winning FUSION package electric water heating systems, POU water heaters cannot avoid it in hard water areas and will exhibit scale problems with some variance in time due to the intensity of use. The problem is that building operators do not maintain


https://adveco.co/


TRILUX and Sweco Deliver Circular Lighting Upgrade in Maidenhead


U


K, July 2025 – TRILUX partnered with Sweco UK Ltd to deliver a circular lighting upgrade at the consultancy's Maidenhead office. By refurbishing and upgrading the existing fluorescent luminaires, the project significantly reduced waste and improved the quality and efficiency of


lighting in the open-plan workspace. Sweco UK Ltd, a leader in sustainable engineering and design, recently partnered with TRILUX to deliver


a circular lighting refurbishment at its Maidenhead office. The project involved upgrading old fluorescent luminaires installed in multi-service chilled beams on the first floor, bringing a more sustainable, energy- efficient, and visually comfortable lighting solution to the space.


A Circular Collaboration The collaboration was underpinned by shared values around climate responsibility, circularity, and the creation of better environments. Both Sweco and TRILUX are committed to the United Nations Sustainable Development Goals and see the transition to a circular economy as key to addressing climate and resource challenges. This shared ambition shaped the project’s approach—from minimising waste through luminaire refurbishment to enhancing lighting quality and workplace wellbeing. TRILUX’s innovative approach to circular economy enabled Sweco to retain and upgrade many of the


existing luminaires, avoiding unnecessary waste and delivering significant carbon savings compared to a full luminaire replacement.


Designing with Sustainability in Mind A successful mock-up helped secure the project, with TRILUX presenting a customised trial luminaire that modernised the appearance and performance of the original fittings. Outdated louvres were replaced with micro-prismatic diffusers, enhancing glare control and visual comfort while preserving the architectural integrity of the space. Conor O'Donoghue, Operations Director at Sweco UK Ltd, commented: “This project demonstrates the impact of thoughtful design and strong collaboration. At Sweco, we aim to lead by example when it comes to sustainability. By reusing and refurbishing rather than replacing, we not only minimised waste but improved the quality of the office lighting for our team. TRILUX supported us every step of the way, ensuring the results met both our operational needs and circular economy objectives.”


A Blueprint for Future Projects The refurbishment marks another milestone in TRILUX’s mission to support clients in making the shift towards a circular economy. It also sets a strong precedent for future upgrades within Sweco's UK office portfolio, proving that sustainable design can sit side-by-side with performance and aesthetics.


www.trilux.com/uk/ Read the latest at: www.bsee.co.uk


Ideal Heating Commercial sails to success with Evomax 2 at prestigious sailing club


T


hree Evomax 2 120kW wall- mounted condensing boilers from Ideal Heating Commercial have


been installed in cascade at Hayling Island Sailing Club in Hampshire, as part of an upgrade to the heating and hot water systems serving the main clubhouse’s busy shower facilities. Founded in 1921, Hayling Island Sailing


Club is located at the entrance to Chichester Harbour and is one of only four Royal Yachting Association coastal Centres of Excellence. With over 3,000 members and a history of nurturing Olympic champions, the club’s facilities are in regular demand, especially during regattas when usage of the shower rooms significantly increases. The original boilers serving the underfloor heating and domestic hot water for the main shower rooms had


reached the end of their service life, prompting the club to upgrade to modern, high-efficiency condensing boilers. Leading building services contractor J&B Hopkins, based in Fareham, Hampshire, was appointed to carry out the installation. A long-time Ideal Heating Commercial customer, J&B Hopkins selected three Evomax 2 120kW boilers to


be installed in cascade, delivering a total output of 360kW. The boilers are mounted on an Ideal Heating low height frame and header kit and installed with plate heat exchangers (PHEX) and preformed insulation kits for complete separation between the primary and secondary circuits. Commenting on the decision, Tony Stockton, Mechanical Project Manager (Technical Services) at J&B Hopkins, said: “We’ve used Ideal Heating Commercial boilers for more than a decade because they’re reliable and very robust. Our Technical Services team installs between 60 to 100 Evomax 2s a year – always with the frame and header kits – because they’re straightforward and engineer-friendly. You could almost fit them blindfolded – although obviously, we don’t!” Highly efficient, the Evomax 2 has up to 99.6% full load efficiency and up to 110% part load efficiency, can


operate at up to 30° ΔT, and features a high turndown ratio of 5:1. At Hayling Island Sailing Club, the cascade setup provides resilience and ensures the heating and hot water system can meet the varying demands throughout the year – from quiet off-season periods to intense regatta days when up to 500 people may shower in a two-hour window. J&B Hopkins also replaced the flue and upgraded the water system as part of the installation. Tony


added: “The support we get from Ideal Heating Commercial is excellent – although we don’t often need it thanks to the boilers’ simplicity. Another big plus is product availability – we can always get the parts we need without delays.”


www.idealcommercialheating.co.uk BUILDING SERVICES & ENVIRONMENTAL ENGINEER AUGUST 2025 27


point-of-use water heaters, so maintenance or, more likely, replacement will be necessitated as the cost of a new unit at £150 does not warrant a £100 maintenance charge. For this reason, POU systems will be subject to a rolling replacement program, which will


subsequently increase a building’s embodied carbon and landfill waste generation. This also brings maintenance personnel into the occupant’s space. Professional offices do not want technicians working in their toilets, whilst many buildings, such as schools, care homes, prisons, or hospitals, have safeguarding concerns with technicians in occupied spaces, who are then carrying out wet, messy work. With the drive to eradicate energy losses not stacking up, as POU standing losses are likely to equal


or even supersede secondary losses of well-designed centralised systems, most commercial buildings should use a centralised hot water system with secondary return and not POU on every floor of shell and core constructed properties. The centralised system is also able to take advantage of low-carbon preheat, whether in the form of heat pumps or solar thermal, that can continue to evolve the system's ability to reduce dependency on energy, reducing carbon emissions and energy costs across its lifetime. On paper, POU electric water heaters appear to be a quick and easy way to distribute hot water throughout a building. But the reality is that throughout the operational life of the building, POU is, unless correctly employed as a terminal fixture away from the centralised system, ultimately expensive, problematic and limited in options for future developments.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38