Costs of improving the thermal performance of houses in a cool-temperate climate

To minimize the energy needed to heat and/or cool houses, the Building Code of Australia requires that new houses meet a minimum level of thermal performance. A star rating system is used to indicate the level of thermal performance a house achieves. Ratings range from 0 to 10 stars. Theoretically, the more stars, the less the energy required for space heating and/or cooling. Currently, most states and territories in Australia require a minimum 5 star performance. However, a minimum 7-8 star rating is likely in the near future. This article examines the capital cost and design implications of significantly improving the thermal performance of brick veneer houses in a cool-temperate climate. The results show that the cost of achieving a certain level of thermal performance varies significantly depending on the methods and materials used, although improvements in thermal performance can be made for little or no cost.