Towards global benchmarking for sustainable homes: an international comparison of the energy performance of housing

Over the past 15 years, house building standards across the western world have begun to address ecologically sustainable development (ESD) principles. Amongst the range of environmental sustainability issues arising from housing construction and occupation, the energy demand for heating and/or cooling to maintain thermal comfort has the longest history and is most widespread in policy and regulation. Since energy in our homes is mainly fossil-derived, a key issue is global climate change impacts. Since greenhouse gas emissions can be emitted in various locations across the globe with similar results, it follows that a given greenhouse gas emission arising from residential space heating and cooling has approximately equal impact, irrespective of the location of the building. These emissions are therefore an appropriate candidate for benchmarking internationally, yet there have been few attempts to undertake this activity. This paper reports on a study undertaken in Australia which compares the thermal energy performance of housing in the United States, Canada, UK and Australia. The comparison is based on energy ratings of over 50 house designs from the comparison countries. Each design was assessed as being current and verified as complying with rather than significantly exceeding local regulatory requirements. Issues in design of both the buildings and the modelling tool used are highlighted, and the results are presented. Conclusions are drawn on the reasons for wide variations in thermal energy performance, the implications for benchmarking, and the case for globally consistent housing environmental performance policies and regulation.