The energy consumption of a house can be affected simultaneously by many building design factors related to its main architectural features, building elements and materials. The relationship between the building design data and energy consumption data of houses can still be identified. This study focuses on the impact of building design factors on the extra winter energy consumption of houses. This information can be used to estimate the approximate saving in extra winter energy consumption, which would result from a changed design datum for future house development, and to identify the major design problems for energy efficiency. The quantitative relationships between building design data and extra winter energy consumption data are also valuable for developing passive design guides for housing energy efficiency. There is a focus on the effects of the passive features used in the architecture.

Based on field study data regarding the winter indoor thermal environment of three classrooms with different building envelopes, this study compared and evaluated these environments, not only related to students’ thermal comfort but also to their health. The inadequacy of the conventional New Zealand school building for maintaining a comfortable and healthy winter indoor thermal environment has been identified. A classroom with thermal mass had 31%, 34% and 9% more time than a classroom without thermal mass when indoor temperatures met 16 °C 18 °C and 20 °C respectively and has 21.4% more time than the classroom without thermal mass when indoor relative humidity was in the optimal range of 40% to 60%, in a temperate climate with a mild and humid winter. Adding thermal mass to school building envelopes should be considered as a strategy to improve the winter indoor thermal environment in future school design and development. Adding thermal mass to a school building with sufficient insulation can not only increase winter indoor mean air temperature but can also reduce the fluctuation of indoor air temperatures. This can significantly reduce the incidence of very low indoor temperature and very high indoor relative humidity, and significantly improve the indoor thermal environment.

The New Zealand Ministry of Health reported that respiratory disease affects 700,000 people, annually costs New Zealand NZ$7.05 billion, and is the third-highest cause of death. The hospitalisation rate for asthma of Māori communities is 2.0 higher than that of other ethnic groups, and hospitalisation rates for deprived homes are 2.3 times higher than those of the least deprived homes. Based on physical data and evidence, which were drawn from a mixed methodology that includes field studies of the indoor microclimate, dust-mite allergens, mould growth, and occupants’ Respiratory Health Survey of a number of sample houses of Māori communities in Minginui, Te Whaiti, Murupara, and Rotorua of New Zealand, the study identifies unhealthy indoor thermal conditions, thresholds or ranges of indoor micro-climate related to different levels of dust-mite allergen and mould growth, the most common type of indoor mould, and correlations between dust-mite and mould and correlations. The study not only identified that the poor health of occupants is closely related to their inadequate living conditions, but also identifies the threshold of indoor micro-climates to maintain indoor allergens at the acceptable level, which can be used as a guideline to maintain or improve indoor health conditions for future housing development or retrofitted old housing.

During winter in Auckland, visible mould growth on indoor surfaces is a relatively common problem in aged residential houses that lack sufficient insulation. Through field studies, the indoor health conditions of a house with mould growth problems are investigated. Through comparison with field measurement data of a new townhouse without mould growth problems, and with an insulation level which complies with the current building code, the indoor psychometric conditions for mould germination and growth under Auckland's climatic conditions are investigated. Practicable methods to estimate and evaluate the indoor psychrometric conditions for indoor health conditions and mould growth in Auckland dwellings are explored.

Previous studies show that moderate thermal mass in school building elements can positively impact the winter indoor thermal environment in a temperate climate with mild, humid winters. Based on a field study, this research contributes new physical data of the summer indoor thermal environment of Auckland school buildings with different designs of moderate thermal mass in their building elements to add to the previous winter field-study data and demonstrates that a school building with moderate thermal mass is adequate in a temperate climate with mild, humid winters and warm, dry summers. This field study compared and evaluated the summer indoor thermal environment of classrooms with different moderate thermal mass in their building elements during the summer school term and the summer school holidays. This study found that a classroom with thermal mass in its building elements has 19% to 21% more time in summer than a classroom without any thermal mass in its building elements when indoor air temperatures are within the thermal comfort zone, which was solely impacted by the building’s thermal performance. This study established a suitable research method to analyse the field-study data and identify the differences in the indoor thermal environments of the school buildings with different designs of moderate thermal mass in their building elements.

Auckland has a temperate climate with comfortable warm, dry summers and mild, wet winters. Previous studies show that Auckland buildings use more energy during winter than other seasons. Auckland building thermal design should focus more on winter indoor thermal conditions. During the winter, high relative humidity can negatively impact indoor health conditions. A conventional Auckland school has a number of low-rise, isolated buildings with lightweight envelopes. In over 90% of Auckland schools, each isolated building only has one to four classrooms. For these types of school buildings, the building envelope becomes the most important design factor for indoor thermal and health conditions. For some energy rating software and design hand books, prescriptions of steady-state R-values ignore the benefits of thermal mass and direct building thermal design towards lightweight wall with high insulation. Based on field study data, this study compares and evaluates indoor thermal and health conditions of classrooms with or without thermal mass in their envelopes.