Passivhaus, also known as Passive House, represents an approach to sustainable building design that prioritises occupant comfort, energy efficiency and environmental responsibility.

Originating in Germany, the innovative standard has since gained global recognition for its holistic approach to creating high-performance buildings. At the heart of Passivhaus are five key principles that guide the design and construction of these durable and healthy buildings — super-insulated envelopes, airtight construction, high-performance window glazing and heat recovery ventilation.

Let’s explore what they involve and why they’re crucial in constructing these high-performing buildings.

Airtight Construction

Airtightness lies at the heart of Passivhaus design, focusing on creating a building envelope that minimises uncontrolled air movement. This meticulous approach not only enhances heat retention but also reduces the need for conventional heating systems.

The benefits of airtight construction also extend beyond energy efficiency. The sealing of the building envelope minimises moisture ingress, safeguarding against insulation degradation and improving the overall durability and lifespan of the structure.

There are many ways to achieve airtightness in Passivhaus construction. Certain materials possess inherent airtight properties, like concrete, while others, like structural insulated panels, feature OSB (oriented strand board) that inherently contributes to airtightness.

In conventional timber stud frame construction, achieving airtightness involves the application of an airtight membrane and then meticulously sealing all joints with tape. Similar strategies apply to concrete panels or structural insulated panels, where joints between panels, floors, walls and ceilings must be carefully sealed.

To learn more about airtight construction within the context of Passivhaus principles, read our comprehensive article on airtightness.

Super-Insulated Building Envelopes

Unlike measuring airtightness with the blower door test, insulation installation doesn’t receive as much scrutiny.

However, incorrect installation will profoundly impact its performance. Even minor gaps or spaces can significantly affect heat loss and gain. Research has shown that a mere 10mm air gap behind insulation boards can double the amount of heat lost by a building through thermal bypass.

That’s why, to achieve Passivhaus standards, insulation must be installed with precision — no gaps, bulges or oversights.

It must be tightly fitted and consistently applied throughout the building envelope, like in the picture above. Continuous thermal insulation of the building envelope is crucial as it helps maintain stable indoor temperatures, ensuring the building remains durable, healthy and comfortable year-round.

Heat Recovery Ventilation

Often referred to as the "lungs of a Passivhaus," a heat recovery ventilation (HRV) system plays a crucial role in maintaining indoor air quality, controlling humidity levels and enhancing overall comfort.

Here's why an HRV is integral to Passivhaus design:

Pollutant Filtration: An HRV system effectively filters out pollutants, dust mites, smoke, and other contaminants, improving the overall air quality within the building — significantly improving the quality of life of individuals with respiratory sensitivities or allergies.

Humidity Control: Controlling humidity levels is essential for preventing mould growth and maintaining a healthy indoor environment. Human activities such as breathing, cooking and showering generate significant amounts of moisture, even though we don’t notice it. If this isn’t effectively managed, it can lead to issues like mould and dampness.

Building Physics and Dew Point: HRV systems help maintain consistent indoor temperatures which minimises the risk of cold spots that could lead to condensation and water pooling. This attention to building physics ensures that Passivhaus buildings remain dry and comfortable year-round.

High-Performance Window Glazing

While triple-glazing is the standard in Europe due to harsher climates, in milder regions like Australia, double-glazing is often enough.

However, the performance of window glazing hinges on various factors such as solar access, orientation and building context. Optimal design and calculations are crucial as areas with limited sunlight or buildings with excessive glazing may require additional heating.

Expert certifiers and designers recommend opting for Passivhaus-certified windows when planning to certify a building as it simplifies the process. These components have the necessary data and performance metrics readily available so you can avoid additional complex calculations.

While using non-certified windows is possible, you’ll need to calculate and account for every thermal bridge. But it can often be the case that manufacturers don’t have this data so it’s a good idea to check and then complete the necessary calculations before ordering windows.

It’s vital to get this part right as even triple-glazed windows can have unaccounted thermal bridges that can push you out of certification range due to not being thermally broken or using highly conductive materials.

Thermal Bridge Reduction

Thermal bridges occur when materials with high thermal conductivity create pathways in a building’s structure that compromise the effects of insulation — like windows and doors.

These can function as highways for heat transfer and are the opposite of what we need if we want to optimise energy efficiency and indoor comfort. To avoid this, the insulation needs to be continuous and thick enough to provide the necessary temperature stability.

If penetrations are made through the insulation, such as with windows and doors, it’s vital to choose less conductive materials or components that have been thermally broken. Thermally broken components are simply high-conductivity materials separated by a low-conductivity material to reduce heat transfer and maintain thermal comfort.

Key considerations for thermal bridge reduction in Passivhaus include:

Detailing Precision: Careful attention to detailing is essential to prevent thermal bridges. Each structural element must be carefully considered and insulated to ensure continuity of the building envelope.

Separation of Structural Elements: Proper insulation and separation of balconies, structural connections and transitions between different building elements are essential to prevent thermal bridging.

Collaborative Approach: Achieving thermal-bridge-free construction often necessitates a collaborative effort among architects, engineers, and builders. Detailing and construction techniques may need to be adapted to meet Passivhaus standards effectively.

Embracing Passivhaus Principles for a Sustainable Future

Whether you are a homeowner, architect, builder, or simply curious about innovative building practices, understanding Passivhaus principles is one way to embrace a more efficient and sustainable approach to construction.

By adopting these principles, we can design and construct buildings that are not only incredibly energy efficient but also comfortable, healthy and resilient. From meticulous thermal insulation and airtight construction to high-performance window glazing, thermal bridge reduction, and heat recovery ventilation, each principle plays a pivotal role in paving the way for a greener, healthier future.

Let's build smarter, build better and build for a brighter tomorrow… Register for our Comprehensive One Day Introduction to Passivhaus Training!

Now that you understand the 5 major principles of Passivhaus, take the next step and deepen your expertise with our Comprehensive Introduction to Passivhaus Training. Designed for newcomers—whether developers, suppliers, trades, architects, engineers, or contractors—this course provides the foundational knowledge you need to excel in Passivhaus building standards.

In this course, you’ll explore:

A deep dive into the 5 major principles of Passivhaus and how to integrate them into your buildings.
The myriad benefits of Passivhaus and their importance in today’s climate.
Passivhaus’ suitability for Australia’s varied climate, its position compared to current codes, and its compatibility with other rating tools.
In-depth discussions on design processes, construction methods, material choices, product options, and more to guide your projects towards better outcomes.
Key considerations at each project stage to achieve high-performance results.

There’s also some great perks that come with the course, including:

A free individual APA membership for anyone who completes the course.
7 CPD points for Architects

This training equips you with the knowledge to pursue further Passivhaus education and apply your learnings for better building outcomes—creating energy-efficient, healthy, resilient, and sustainable buildings. Plus, gain insights from industry leaders through real-world case studies.

Don't wait—register now to transform your building projects and stay ahead in the field! Register now

What is Passivhaus? Its 5 Principles Explained