We analyse the time and volume distributions for hot water consumption using data acquired from seven New Zealand households. This shows that there is a high proportion of low volume draws, 50 per cent yielding less than 2–31, depending on the household. In addition draws tend to be separated by relatively short intervals, 50 per cent following the previous draw by not more than 10–20 min. By use of a dynamic model of the hot water piping we estimate that thermal losses in the piping exceed 20 per cent of the heat energy supplied by the hot water cylinder for average households. We show that the use of pipe insulation may reduce these losses by 5–7 per cent.