A method has been developed at Uppsala University, Sweden, to generate hot water load profiles for households [5, 6]. The model aims at presenting the daily distribution of hot water demand between different individual households as well as average Swedish households based on peoples’ statements about their activities. The input to the model is time-use data from so called time diaries, and the model converts the activity data into hot water volumes and energy use. The material constituting the base of the model is a pilot study on time-use performed in the autumn of 1996 by Statistics Sweden, which was later coded at Linkoping University [8]. The households were selected by Statistics Sweden and the selection is assumed to be representative for Swedish households. It should be noted that the time-use study did not focus on energy use, but on time-use in general. Therefore, the participants are assumed not to have manipulated the time statements to look better from an energy perspective.

A total of 464 persons in 179 different households living in detached houses and apartments participated in the study. The participating household members filled in all the activities they performed, the duration of the activity as well as accompanying persons, among others in the time diaries. The diaries were recorded for one weekday and one weekend day, specified by Statistics Sweden, by all household members older than ten years. By connecting parameters describing the assumed type of tapping (extension in time and draw-off pattern) as well as the amount of hot water to

different activities a model was developed in the computer program Matlab. The hot water volumes for different activities as well as temperatures can easily be varied to suit possible known conditions.

The model output is hot water profiles in volumes or energy/power for individuals, households or groups of people, separated in apartments and single-family houses. Different time resolution can be chosen, from five minutes intervals, which is the time resolution mainly given in the time diaries, up to one hour. The model can also be applied to any time-use data organised similarly to the basic data set.