Passive-solar design: Evidence of the disconnect between theory, policy and practice in the glazing design of contemporary Australian homes

Theories of climate responsive passive-solar design are well understood to be a fundamental aspect of energy efficient housing design. However, in contemporary housing design practice, active heating and cooling technologies are ubiquitous to provide occupant thermal comfort, consequentially with a significant dwelling energy demand. The complementary use of passive-solar design can reduce active heating and cooling energy demand. However, there is limited understanding of the prevalence of this in mainstream practice. Glazing design is a fundamental aspect of passive-solar design, and the presence of climatically appropriate glazing size, orientation and materiality provides an indication of the application of passive-solar design. This research contributes a novel transferable methodology to delineate the large-scale prevalence of passive-solar glazing design across disparate climates. Through analysis of 584,041 thermal energy design certificates for new detached Australian homes between 2018 and 2022, this study assessed glazing scale, orientation and materiality. In regions with more challenging warm/hot-summer or cool-winter climates over 75% of certificates demonstrated at least one parameter of passive-solar glazing design. However, 81% of new home certificates were located in milder temperate climates where passive-solar glazing design parameters were demonstrated in less than 20% of certificates. Nationally, this study found less than one-third of new home certificates demonstrated passive-solar glazing design, suggesting housing energy policy in Australia did not encourage the practice of climatically responsive passive-solar glazing design on a national scale. There is substantial scope to increase the practice of climatically appropriate passive-solar glazing design and reduce national energy demand for housing thermal comfort.