The Importance of Air Tightness in Australian Homes

Recent research conducted by CSIRO, Australia’s national science agency, has shed light on the air tightness levels of new Australian homes. The study revealed that homes built in the last four years are up to 50% more airtight than those tested in 2015. This is significant news for homeowners, as achieving recommended air tightness levels in homes can lead to increased comfort, lower energy bills, and healthier indoor air quality.

Airtightness plays a crucial role in minimizing unintended air movements within a building, preventing outdoor air from entering and indoor air from escaping. When a home is not sufficiently airtight, drafts can occur, leading to an increase in energy bills by up to 20%. On the other hand, homes that are too airtight without controlled ventilation can result in issues such as condensation, mold growth, and health problems for residents, including headaches and nausea from elevated carbon dioxide and monoxide levels.

The Study Findings

The research involved testing 233 apartments and detached houses in major Australian cities like Melbourne, Sydney, Canberra, Brisbane, and Adelaide. Homes specifically designed for air tightness were excluded from the study. The results of the research were positive overall, with the tested homes comparing favorably to standards in countries like the U.K. However, the study also identified areas for improvement.

Senior Experimental Scientist Michael Ambrose, who led the project, highlighted that leakages were commonly found in most new homes, particularly from bathroom fans, sliding doors, and deficient or missing door seals. Some apartments, in particular, were noted for being extremely airtight, which can have negative implications for both building performance and resident health if adequate ventilation systems are not in place.

Recommendations for Improvement

The report put forward a series of recommendations aimed at addressing common air tightness issues in Australian buildings. These recommendations included advocating for the establishment of air tightness standards in the National Construction Code (NCC), mandating controlled ventilation in new buildings, especially apartments, to mitigate indoor pollutants and moisture, making air barriers like building wraps compulsory in all new residences, and providing training and educational resources to builders on cost-effective solutions that enhance building performance.

Furthermore, the study highlighted that the actual air tightness levels observed closely corresponded with those assumed by the Nationwide House Energy Rating Scheme (NatHERS), which assigns an energy efficiency star rating to residential buildings. This alignment provided researchers with confidence in the accuracy of NatHERS in predicting air tightness within specified levels. There is potential value in disclosing air tightness values on NatHERS certificates and highlighting their impact on the star rating.

The research conducted by CSIRO underscores the importance of air tightness in Australian homes and the benefits associated with achieving optimal levels of airtightness. By addressing common air tightness issues and adopting the recommended measures, homeowners can enhance the comfort, energy efficiency, and indoor air quality of their residences. It is imperative for policymakers, builders, and homeowners to prioritize air tightness in the construction and maintenance of homes to create healthier and more sustainable living environments.