Passive House

Passive House is a design concept that creates buildings that use up to 75% – 90% less energy than conventional construction. The byproduct of which produces indoor spaces are more comfortable, have better indoor air quality, and are significantly quieter.

Passive House is a general term that applies to all building types and is not specific to any building style. While many Passive Houses are single family homes, there are also a growing number of Passive House schools, apartment buildings, fire stations, car dealerships and government buildings of all types.

And while many believe small buildings to be more efficient, Passive House concepts work significantly better and are more cost effective on larger buildings. This is because as a building gets larger, there are fewer exterior walls compared to the heated or cooled area and volume within the building.

Early beginnings

[bundle] started using Passive House design in 2013 with the Birch Case Study House. We chose to follow Passive House as the building science lends itself to the most efficient, comfortable, healthy and durable buildings possible. Since 2013, [bundle] has completed hundreds residential projects. While most of these projects are not fully certified Passive House projects, all our projects follow the passive design principles to ensure sustainable buildings for a low carbon future.

Walking the Talk

While we preach the comfort and efficiency of Passive House, it wouldn’t be right to work out of a drafty, uncomfortable, high energy use office building. For this reason, in 2020 [bundle] designed and developed one of the smallest certified Passive Houses in the world as our headquarters (see projects page). This allows us, to not only work in a healthy, comfortable building, but to show clients and community the benefits of Passive House over conventional construction.

Performance Standards

Unlike other green building certification programs, Passive house focuses on three performance metrics:

Thermal Energy Demand – Passive house sets limits on the total amount of heat/cooling energy used within a building. A lower energy consumption reduces a building’s operational costs and carbon emissions.

Energy Demand – Passive House sets limits on the overall energy used to operate a building and includes heating, cooling, plug loads, lighting, etc..

Air Tightness – Passive house sets limits on the “leakiness” of the building’s envelope. A tighter building ensures a durable, healthy and energy efficient building. The air tightness is tested with a blower door test to ensure performance, and when combined with high-quality ventilation, delivers superior indoor air quality.

Passive House Design Priciples

Passive House - Continuous Insulation

Continuous Insulation

The building envelope (exterior walls, roofs and floors) of a Passive House are wrapped with a continuous layer of insulation. The amount of insulation is determined by the climate in which the building is constructed. What is most important is that this insulation is uninterrupted with as few gaps as possible to keep the heating or cooling inside the building.

Passive House - Thermal Bridge Free

Thermal Bridge Free Construction

A material or building element (framing, beams, balcony, etc.) that extend from interior to exterior are called thermal bridges. These elements are locations of extreme energy loss and create the increased risk of condensation that causes mildew, mold and deterioration. Passive House buildings design out these weak spots and ensure the building is more efficient, comfortable, healthy, and durable.

Passive House - Air Tight Fresh Air

Air Tight Construction + Fresh Air Ventilation

A Passive House is built with as few air leaks as possible. An airtight layer prevents heating & cooling from escaping the building and unwanted hot or cold air from the entering the building. This airtight layer prevents the building from being “drafty”, unnecessarily losing energy to the outdoors, and promotes durability by limiting water leaks and formation of condensation that lead to mildew, mold and deterioration. 

Once an airtight structure is constructed, constant filtered fresh air with heat recovery is delivered to the building to provide the best indoor air quality. HRVs (heat recovery ventilators) or ERVs (energy recovery ventilators) provide “balanced ventilation” that supplies continuous fresh air while simultaneously exhausting polluted indoor air from kitchens and bathrooms. Because these units have heat recovery, the air that is delivered to the space is much more comfortable that opening windows in uncomfortable conditions such as the middle of winter. Additionally, the fresh air supplied is filtered of pollen and other outdoor pollutants. This is important with the increase in wildfire seasons across much of North America. 

Passive House - High Performance Windows

High Performance Windows & Doors

Windows and doors, while being the eyes of the building are also the weakest link in an efficient building enclosure. To ensure comfort, health and efficiency, Passive House buildings use windows that perform to a higher standard. As an occupant, this allows you to sit much closer to windows without feeling the uncomfortable radiant cold in the winter and radiant heat in the summer.

Passive House - Daylight Solar Gain

Solar Control

Passive Houses are oriented to take advantage of the sun’s free energy. While this is a welcome commodity in the winter (in most climates) it can cause overheating in the summer. For this reason, Passive House buildings are designed to allow winter sun energy to enter the building but is shaded from the harsh summer sun.


At [bundle], every team member is well versed in Passive House design and we are moving to make every employee a Certified Passive House Consultant. While we do all our own design work for Passive House projects, [bundle] also offers Consultation for outside projects to apply the Passive House concepts that create a more healthy, comfortable, efficient, and durable building.