Towards dwelling energy certification for New Zealand: normalisation issues

Abstract

With the impact of climate change, the use of both energy and resources that lock in future energy use is receiving heightened attention. New Zealand has lagged behind many similar countries in not requiring an explicit energy certification for dwellings. This paper reviews the form of energy certification used by similar countries and discusses the potential impact of applying the various forms to New Zealand dwellings. Specifically, it compares how different forms of comparison, or normalisation, value the features of a home and implicitly rate which dwellings are considered ‘like’ each other. Of the 85 buildings compared none received consistent rankings across all the normalisation methods and only one was in the ‘better’ half of the data under all nine of the normalisation methods used. Some of the forms of normalisation systematically advantaged large dwellings, and others small dwellings. Since normalisation methods can be chosen to value certain aspects of dwelling design, there needs to be a discussion about what we value in dwellings in order to determine which method(/s) would be appropriate for New Zealand. The main purpose of this paper is to alert social scientists of the need to have this value-based discussion.