Pergamon Energy Convers. Mgmt Vol. 39, No, 7, pp. 679-684, 1998 © 1998Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0196-8904(97)00048-4 0196-8904/98$19.00 + 0.00 DOMESTIC HOT WATER CONSUMPTION IN SOUTH AFRICAN TOWNHOUSES J. P. MEYER and M. TSHIMANKINDA Research Group for Coolingand HeatingTechnology, Laboratory for Energy,Engineering Faculty, Rand Afrikaans University, PO Box 524, Auckland Park, 2006, South Africa (Received 3 September 1996) Abstract--Hot water consumption for townhouses in Johannesburg is determined with measurements over a period of 1 year. The results of two types of measurements are presented. Firstly, hot water consumption per person per day for the different months of a year. Secondly, hourly hot water consumption per person per day as a function of summer weekdays, summer weekends, winter weekdays and winter weekends. © 1998 Elsevier Science Ltd, Hot water consumption Domestic Townhouses INTRODUCTION Because of the very mild climate of South Africa, hot water consumption--and not space heating--is the largest user of energy in the domestic sector. Estimates vary, but figures as high as 40-50% of the monthly electricity use of an average middle-to-upper income household have been quoted in the South African Energy Policy Discussion Document [1]. In South Africa, three sources of reference on hot water consumption are known, the first being Basson [2] in which a value of 501 per person per day is quoted for developed communities. The second source of information on hot water consumption is that of Meyer and Greyvenstein [3], which endorses the value of Basson in the summer, but adapts the value for the rest of the season with a cosine function. This implies that the average hot water consumption per person varies between a minimum of 50 1 during December (summer) and 75 1 during June (winter). These data are, however, only used in, and applicable to, the average developed community of South Africa. The third source on hot water consumption rates is that of Beute [4] in which a figure of 35 1 per person per day for people in developing communities is suggested. The figure is, however, an assumed consumption, which was not based on any measurements. It is, therefore, clear that no reliable data exists for hot water consumption in South Africa, although the values of Meyer and Greyvenstein [3] are used by many engineers in the industry. Even though there is a possibility of using the database developed by Becker and Stogsdill [5] for the U.S.A., Schipper [6] found that Americans use up to seven times more hot water than the citizens of certain developed European countries. Schipper, as well as Vine [7], concluded that hot water consumption is influenced by cultural and social norms. Therefore, although a well-established database system is available on the hot water consumption patterns of Americans, it cannot be applied to the South African situation. The purpose of the present study is to present results from measurements taken in townhouses in Johannesburg, South Africa. 679