What was born out of a legal requirement for construction of buildings with low energy consumption in Europe has now become a global standard and sought after solution given the impacts of climate change – hot summers, cold winters and expensive heating & cooling costs. Now known as Passive House, these buildings with highly engineered energy efficiency and stringent design standards can cut energy use by 90%.

The Passive House Institute (PHI) (Darmstadt, Germany) is an independent research institute that has played an especially crucial role in the development of the Passive House Standard concept – the only internationally recognised, performance-based energy standard in construction.

The Passive House standard is designed to ensure homes offer maximum quality, comfort, and energy efficiency. The end goal is for the structure to require a minimum amount of energy to achieve a comfortable, year-round temperature, making obsolete conventional heating and air conditioning systems.

International Passive House Association

1988 the First Passive House

The first passive house was launched in Germany in 1988 by Wolfgang Feist and Bo Adamson, who also wrote the book “Building Physics Basics for Heating Buildings” which helped establish a new way of building homes that consumed less energy. Their research evolved into what would become known as Passivhaus.

Net Zero House vs. Passive House

Net Zero and Passive House are related concepts. The use of the term “Net-Zero” was introduced in the context of greenhouse gases and was quickly adopted in many industries.

A Net-Zero house produces as much energy on an annual basis as it consumes. Design and engineering usually involve energy-efficient technology and renewable energy sources to reach zero net energy use throughout the year. It starts with an energy-efficient building envelope (walls, foundation, roof), high-quality windows, and high-efficiency heating and ventilation systems to keep the overall consumption as low as possible.

Passive House Windows

Passive house windows are built to the specific energy efficiency performance of the Passive House Standard. It is widely considered to be the world’s leading standard in energy-efficient home construction.

For a Passive House certified building the required U-value in the US and Canada must be less than 0.80 W/(m2.K). A Passive House certified window U-value is used for product comparisons and provides input for the project-specific details when completing the Passive House Planning Package. The project U-value will depend on the quality of the window installation.

Installation is key

Proper installation and positioning of the windows within the building envelope ensures the windows perform at their optimum level. Passive House windows are installed in very deep reveals to reduce solar gains during summer and minimize overheating. Thermal bridges can occur if a window is installed incorrectly.

In Passive House applications the window is placed within the insulation layer of the wall, covering some of the window frame to further mitigate or eliminate heat transmission through the frames and the window reveals. The installation of airtight tapes must also be carried out correctly to ensure the airtightness layer remains continuous. For aluminum clad windows insulating over the frame doesn’t have any effect on their performance.

Our Passive House Partners

Our partner Freisinger Fensterbau offers OPTIWIN, a complete line of Passive House certified wood-aluminium window, lift and slide door, and façade systems. Founded in 1932 in Austria, this fourth generation manufacturer values sustainable production.

OPTIWIN is the world’s first coordinated, complete system for windows, sliding doors, front doors, and facades – all certified by the Passive House Institute Dr. Feist, Darmstadt (Germany). Learn more about OPTIWIN products.

Lunch & Learn

We offer a Lunch & Learn focused on Windows & Doors for Passive House projects. To book a Lunch & Learn or for more information on our compliant product lines contact Edward Klenk at 647-808-4711 or