Estimating waste heat from domestic hot water systems in UK dwellings

Domestic Hot Water (DHW) production can account for a quarter of the energy consumed in UK dwellings and this proportion is likely to increase as the energy required for space heating reduces in order to achieve demand reduction targets. As the margins for improving the performance of heating system technologies diminish, the need for improving modelling accuracy and precision increases. Although studies have considered DHW use, there is a lack of reflection on the consumption and performance of systems in contemporary UK dwellings. This paper is based on two family homes and investigates heat losses from DHW networks using high resolution demand data combined with an analytical model. The model estimates are compared to widely used building performance models and it is found that the models may over estimate the heat losses by a significant amount and that short draw-offs are particularity influential in determining the amount of heat wasted.