Vienna House Passes Key Passive House Testing

On April 10, Vienna House reached a significant milestone in its longstanding goal of achieving Passive House certification.

Creating housing that supports people and communities means planning for the long term. From the beginning, the Vienna House project team committed to achieving Passive House certification to provide homes that are healthy, comfortable, and energy efficient.

What is Passive House and why is it important for Vienna House?

Passive House is a voluntary building standard that creates highly energy-efficient homes with consistent indoor temperatures, excellent comfort, and good indoor air quality. It also helps keep the building affordable to operate, contributing to lower utility costs throughout its lifetime. These benefits extend beyond the building itself, supporting a healthier, more sustainable community and a better quality of life for residents.

Passive House is a major commitment. To achieve certification, the project team must design the building to meet strict performance standards. These standards include:

• Energy efficiency
• Airtightness
• Fresh-air ventilation

They also need to provide detailed documentation and computer modelling throughout the project. Before certification is granted, the building must pass independent testing to confirm it meets the required standards.

That’s what happened in early April, when a team from RDH Building Science completed a blower-door test on the Vienna House project site.

A Passive House building must be tightly sealed to keep indoor heat from escaping in winter and unwanted outdoor heat from entering during summer heat events.

What is a blower door test?

The blower-door test checks the airtightness of a building’s enclosure, or envelope, by measuring the amount of air that leaks through exterior walls. Here’s how it works:

Technicians first seal off an exterior doorway with a fabric enclosure and an integrated large electric fan. Much like a very powerful kitchen range hood exhaust, the fan pulls air out of the building, which lowers the indoor air pressure.

Outside air then tries to enter through tiny cracks and gaps in the building, particularly around windows, doors, and vents.

Using instruments attached to the fan, the technicians measure the pressure difference between indoors and outdoors, and the precise amount of airflow the fan needs to maintain that pressure difference.

If the building is well-sealed, the fan does not need to move much air to hold the target pressure. But if there are cracks and leaks in the building envelope, it needs to move more air to do so. The early-April test confirmed that Vienna House is now sealed to 0.6 air changes per hour (ACH), the threshold required for certification.

While important, airtightness is not the only Passive House requirement. Project teams must also pay close attention to insulation, windows, and the orientation of the building. This helps optimize solar warmth in winters and provide shading from the sun in summers. Computer modelling helps ensure the building will use very little energy for heating and cooling.

Vienna House is not only an apartment community. It is also a real-world demonstration of housing innovation, including sustainability innovation.

Why Vienna House is Aiming for Passive House

Sustainability is a core focus at BC Housing and one of the organization’s three key commitments. Vienna House provided an opportunity to show how innovation and high-performance building design can support both sustainability and long-term affordability.

Passive House projects are not only very energy efficient but also produce very low carbon emissions. Both the City and the Province of British Columbia have adopted policies and targets intended to transition new buildings toward zero operational carbon emissions over time. These principles align with BC Housing’s Strategy 2030 goals to advance sustainable housing and reduce the environmental impact of new developments.

As an additional benefit, Passive House buildings are very quiet inside, due to their use of triple-pane windows. The project team knew this would help minimize the impact of noise on residents from the SkyTrain line that runs along the north side of the site, improving their quality of life. Vienna House shows how the Passive House approach can bring together energy performance, long-term affordability, and resident well-being in one cohesive design.

Other BC Housing Passive House Communities

Vienna House is not the first BC Housing project to target Passive House. Other BC Housing-funded communities that have achieved certification include:

• Naatsumaat Lelum (“We Are One House”), a 25-unit affordable rental multifamily housing development in Nanaimo, on the traditional territories of the Snuneymuxw First Nation. The Tillicum Lelum Aboriginal Friendship Centre operates the building.
• Juniper House, a 30-unit apartment building in Merritt, BC, for individuals who have experienced homelessness and/or chronic illness, and who would benefit from affordable housing with supports. The ASK Wellness Society operates the building.
• Dik Tiy (“High Road”), a 19-unit housing building in Smithers BC providing housing for adults with developmental disabilities and low-income seniors. The Dik Tiy Housing Society operates the building.

Vienna House is expected to join the ranks of the above projects later this year, once all of the information and reports are submitted to the Passive House Institute for review.