Energy Efficiency, Indoor Air Quality and Health in New Zealand’s Traditional Domestic Architecture

Abstract

New Zealand has often been held up as a pristine, natural place, but this state appears to be at risk from the rampant growth in energy demand and poor living conditions. Besides being energy-consuming, New Zealand homes are known for having cold, damp and uncomfortable interiors. Furthermore, the country has one of the highest incidences of asthma and respiratory related illnesses in the developed world. Considering that around 900,000 homes of the country’s current housing stock of approximately 1.6 million is made up of poorly performing homes in terms of both energy and Indoor Environmental Quality (IEQ), their renovation appears the most sustainable approach to provide comfortable and healthy living standards while preserving the architectural heritage. Besides old timber frame buildings, which were – and often still are – completely uninsulated, many new and renovated homes have been designed and built with low quality insulation and heating systems, and a lack of adequate ventilation. Furthermore, the energy performance upgrade of the existing building stock, ongoing since 1978, has changed the buildings’ physical behaviour, generating new and unexpected problems. This paper addresses the lack of information about IEQ in New Zealand’s homes, investigating the existing building stock – from early colonial cottages to contemporary buildings - in relation to present-day multilayered wellbeing needs and energy efficiency requirements. It focuses on the urban fabric of Auckland - major NZ metropolitan area and perfect example of contemporary sprawl – and identifies the most representative building clusters and typologies, providing a detailed assessments of selected types in order to develop new retrofitting procedures. Starting from the analysis of the existing building stock, in relation to orientation, construction details, insulation level, ventilation and humidity, the paper finally provides practical recommendation for the refurbishment of existing dwellings in order to enhance building energy performance and occupants’ living condition.