BALANCING USER COMFORT AND NETWORK EFFICIENCY
Josh Collins, Heat Networks Manager at Altecnic, explains the role of ‘keep warm control’ in HIUs, identifying the risks of poor management, technical strategies for effective implementation, and best practice guidance.
Heat Interface Units (HIUs) are central to the performance of heat networks. While much focus must be given to primary pipe sizing, central plant efficiency and system hydraulics, one area that is frequently underestimated is ‘keep warm control’. Too often it is dismissed as a “comfort setting” for residents, yet in practice it can strongly influence user satisfaction, energy efficiency, return temperatures, and long-term operating costs. Keep warm control must be treated not as a minor feature, but as a strategic control parameter for both occupant experience and network performance.
The growing deployment of district and communal heating systems across the UK is reshaping the way heat is delivered to multi-residential buildings. HIUs serve as the bridge between the central heat source and individual dwellings, providing space heating and domestic hot water (DHW) through indirect or direct arrangements.
A recurring challenge is balancing the need for responsive hot water delivery with the wider requirement for low return temperatures and energy efficiency. Keep warm functions are designed to ensure that DHW is available quickly – but if not carefully managed, they risk becoming uncontrolled bypasses that undermine the performance of the entire network.