Measurement of domestic hot water consumption in hotel rooms with different basin and shower mixing taps

Abstract

Domestic Hot Water (DHW) production constitutes a significant proportion of the energy demand of modern buildings, and as the building envelope is improved the share increases. This article shows results from a measurement campaign on two equal hotel blocks, in the same hotel. There are different basin and shower mixing taps installed in the two hotel blocks, one with original mixers (13-14 l/min) and one with touch-free operated water saving mixers (5-6 l/min). The number of guests were registered separately for the two blocks. The results indicate almost a one-to-one relationship between the difference in mixer and total water consumption, resulting in a potential energy saving of 50-60%. There are no indications that the reduced water flow results in increased duration of each individual shower. However, it is not known if this is due to the use of touch-free operated mixers. Feedback through complains from guests indicate somewhat reduced perceived comfort level from the water saving mixers, and some annoyance caused by the touch-free operation. The results indicate that optimal balance between user comfort and water saving is slightly higher water flow than the applied 5-6 l/min.