What is a Passive House?
Passive House is the world‘s leading standard in energy efficient design. It uses approximately 90% less energy for heating and cooling and reduces the primary energy usage about 75% from existing building stock. It started out as a construction concept for residential buildings in Central Europe. Today, the Passive House Standard can be implemented in all types of buildings almost anywhere in the world.
A building is called a Passive House when it is constructed with the Passive House methodology and meets the Passive House Standard criteria. A Passive House can be any type of building: an apartment building, a school, an office building, a factory, a supermarket. Passive Houses are exceptionally comfortable, healthy and affordable to occupy. A Passive House may become a Certified Passive House. Sometimes it is not possible for a building that was designed and built with the Passive House methodology, incorporates Passive House components to meet all required criteria. The building may be called a Passive House Project, or more generically a high-performance low-energy building. See our Passive House Apartment as an example of this.
Designing a passive house
When designing a Passive House one first attempts to minimize the heating and cooling loads as much as possible through passive measures like orientation, massing, insulation, heat recovery, passive use of solar energy, solar shading, elimination of thermal bridges, and incidental internal heat sources. A good comparison is to create a thermos bottle. But because the building is airtight it requires mechanical ventilation. A continuous low volume supply of filtered fresh air is supplied to living/working spaces and stale air is exhausted from services spaces – providing balanced and controlled ventilation with high-efficiency heat recovery. The incoming outdoor air can be filtered to reduce allergens and pollution. All necessary building information be entered into the Passive House Planning Package (PHPP) which calculates the building energy balance (heat losses and gains), cooling loads and primary energy use. The PHPP is the essential design tool in making a successful Passive House.
Why Passive House?
Energy Efficient: It provides a dramatic reduction in energy use, up to 90% for heating and cooling demand from average existing building stock – in an effort to offer a useful response to the climate crises.
Healthy: Fresh, high-quality indoor air, free of mold and dangerous levels of typical indoor air contaminants.
Comfortable: A quiet interior environment with consistent temperatures and no drafts.
Affordable: The added construction costs for high performance are substantially offset by a reduction in systems sizing. Because the reduced energy use translates into lower bills and protection from future energy crises, occupancy is affordable.
Resilient: Passive House buildings help provide resiliency in three ways. 1) By indefinitely maintaining habitable interior temperatures in freezing weather without power – allowing people to shelter-in-place. 2) By reducing power demand, which allows power distribution systems to be better managed. 3) By reducing power demand to make Net Zero Energy building readily achievable with rooftop photovoltaic solar panels and/or other renewables.