Building Science
Passive House
A performance standard for very low heating and cooling demand, reached through airtightness, continuous insulation, heat-recovery ventilation and controlled glazing. Two certifying bodies publish different criteria.
In more detail
Passive House is a performance standard for buildings with very low heating and cooling demand. It is defined by outcomes rather than prescribed assemblies: an annual energy demand limit, a peak load limit, and an airtightness limit verified by blower door test.
The physics that gets a building there is consistent — a continuous air barrier, continuous insulation with thermal bridges deliberately reduced, high-performance glazing sized and shaded by orientation, and balanced mechanical ventilation with heat or energy recovery, because at that airtightness there is no accidental ventilation left to rely on.
Two organizations certify against different criteria. The Passive House Institute maintains the original international standard, including a 0.6 ACH50 airtightness requirement. PHIUS publishes a separate North American standard with climate-specific targets, on the argument that a single absolute demand limit behaves differently in Minneapolis than in Lisbon. A building described as Passive House may be certified under either, certified under neither, or simply built to the principles — three different claims.
Why it matters
Passive House matters to a homeowner less as a certification than as the most rigorous available demonstration that enclosure-first sequencing works. It also carries a consequence worth understanding before committing: at that airtightness, mechanical ventilation is not optional and its commissioning is not a formality. The requirements are a design constraint from day one, affecting massing, glazing area and orientation rather than being added during construction.
The common misunderstanding
That Passive House means passive, or means no mechanical systems. A certified building has a designed, balanced, continuously running ventilation system and usually a small active heating and cooling source. The word describes how little energy the enclosure needs, not an absence of equipment.
Related terms
On Compound
Where this term does real work — and where the decisions get made.
Sources
Last reviewed July 2026 by Compound Editorial. Definitions are educational and not project-specific engineering or medical advice.