Passivhaus

THE GOLD STANDARD IN ENERGY EFFICIENT BUILDING TECHNIQUES

Modern single-story house with wood and black exterior, pitched roof, front porch with plants, and landscaped yard.

What is a Passivhaus?

A Passivhaus is a house that requires very little energy to maintain a constant, pleasant temperature. In this sense, such buildings are almost “passive” as they need hardly any active heating or cooling to stay comfortable year-round. Excellent insulation and highly efficient heat recovery systems make this possible. The concept is about intelligent design: reaching the desired goal with minimal use of complex systems and non-renewable resources.

Modern house with wooden exterior, solar panels on the roof, and outdoor seating on a deck.

What are the Passivhaus benefits?

Energy efficiency lies at the heart of the Passivhaus concept. Over the course of a year, a Passivhaus building uses no more than the equivalent of 1.5m³ of natural gas (15kWh) to heat each square metre of living space. This can equate to a more than 90 percent reduction in space heating and cooling energy use as compared to consumption in typical building stock. In comparison, a conventional new build still requires 6 to 10 or even more cubic meters of natural gas (15kWh) per year and square metre of living space, depending on building quality and location.

The Passivhaus principles

Thermal Insulation

Insulation is calculated to the home’s geographical location and included within the building’s envelope, providing enough thermal separation between the heated or cooled conditioned inside environment and the outdoors. This improves thermal comfort and reduces the risk of condensation (no more cold internal surfaces in winter!). This also greatly reduces the risk of mould.
Passivhaus (High Performance) Windows

Low-emissivity windows in a passive house to ensure superior levels of insulation. The size of the windows are accurately calculated to each orientation, to allow solar radiation to penetrate during the winter months (free heating!). Exterior shading, whether fixed or movable, is of critical importance in blocking solar heat gains during the summer period.
Ventilation Heat Recovery

Passivhaus buildings incorporate a superior ventilation system that ensures ample fresh air at room temperature and makes for high indoor air quality. This mechanical ventilation unit effectively recovers warm air and cool air that would otherwise be wasted whilst also filtering the air that’s coming into the building. This leads to fewer pollutants in the air and a lower risk of condensation meaning a healthier indoors. Yes, you can also OPEN your windows!
Airtightness

An essential part of every Passive House is an airtight building envelope. This ensures that there are next to no gaps or cracks within your envelope, giving you full control over your internal environment and significantly improving thermal comfort – no more drafts.
Thermal Bridge Reduced Design

The insulation not only needs to be sufficient in thickness but also needs to be continuous. This means keeping penetrations through the insulation to an absolute minimum, and if not avoidable then using materials that are less conductive to heat (i.e. timber in place of metal) and/or incorporating thermal breaks (whereby a material that doesn’t conduct heat well separates the two conductive elements).