The principles of airtightness are well understood in the context of Passivhaus. With strict Air Changes per Hour (ACH) requirements (0.6ACH50), it allows for the effective use of mechanical systems to maintain temperature and humidity while minimising energy loss compared to leaky buildings. An often-overlooked advantage is that by keeping the structure both airtight and wind-tight, you can maintain the effectiveness of the thermal insulation layer. This is a significant factor in high-performing structures. As air is pushed over and through an insulation layer, it can drastically reduce its effectiveness. When testing wall assemblies, “Wind washing led to an 85%reduction of thermal resistance in the examined structures." (Piotr Kosiński, 2019)
Greater comfort
Passivhaus accounts for thermal bridging and the effective thermal resistance of walls, roofs and windows. This allows for a comfortable, dry and passively temperature-controlled environment. It also reduces the risk of cold spots at external corners and complex geometries throughout the building, drastically reducing mould risk. Think fresh air without draughts, and warm temperatures without heating.
Energy efficiency
When all the principles are combined within a passive house:
· minimising thermal bridging,
· high-performing structures,
· high-quality glazing,
· mechanical ventilation
· high levels of airtightness
The key drawcard across the world are the large energy savings that come with reduced heating and cooling requirements. The concept of Passivhaus is based on building physics, delivering an optimal living environment with minimal energy demand.
Passivhaus around the world
On 19 May 2010, the European Parliament formally adopted the Energy Performance of Buildings Directive (EPBD), which required that all new buildings be "nearly zero energy buildings" by 31 December 2020, with public buildings meeting this standard two years earlier. In Scotland, mandatory airtightness testing for all new dwellings was introduced in October 2011 under Section 6 of the Scottish Building Regulations, with standards tightened further in 2023. Scotland has since gone further still, working toward a Scottish equivalent of the Passivhaus standard for all new housing. Similarly, in North America, IECC 2012 introduced mandatory measured airtightness requirements for residential construction as a model code. Many jurisdictions have adopted this into law, introducing mandatory measured airtightness levels for residential construction, while ASHRAE standards are often used to govern commercial buildings.
Passivhaus is becoming increasingly relevant in Australia
The National Construction Code (NCC) 2025 represents a major shift in Australian building standards, increasing minimum thermal performance requirements and introducing greater focus on energy efficiency and condensation management. While these changes improve the performance of new homes, Passivhaus principles go even further by focusing on a high-performance building envelope, exceptional airtightness, thermal comfort and long-term durability.
Passivhaus construction focuses on climate-responsive design, high-performance insulation, airtightness and controlled ventilation to help manage heat, moisture and indoor air quality. This approach helps create healthier, more comfortable and energy-efficient buildings while reducing condensation and mould risk.
Certified airtightness systems
Intelligent Air Barriers like Pro Clima’s INTELLO® PLUS support the growing shift toward Passivhaus and high-performance construction in Australia by helping create healthier, more durable and energy-efficient buildings suited to our varied climate conditions, while reducing condensation and mould risk.
INTELLO Plus protects the structure from vapour drive while maintaining a highly airtight yet vapour-variable membrane, with up to 100x diffusion variability depending on humidity. This makes it well suited to managing moisture risk across many Australian climates.
With certified airtightness systems, tested tapes and sealants, and reliable detailing solutions for junctions and penetrations, Pro Clima provides builders, designers and installers with complete systems they can trust to deliver long-term performance.
Learn more about Pro Clima
Photograph by Marnie Hawson of Binowee Hemp Haus by Gruen Architecture & Sanctum Homes
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