Passive House
An extremely energy-efficient building standard, certified either by the Germany-based Passive House Institute or, on most US projects, by PHIUS, a separate American certifier using its own climate-zone-specific targets, achieved primarily through an airtight building envelope, high levels of continuous insulation, and heat-recovery ventilation, rather than relying on renewable energy generation or efficient mechanical equipment alone to hit its energy targets.
Why it matters
Passive House's airtightness requirement is verified through a mandatory blower-door test with a genuinely demanding numeric target, far stricter than typical energy code requirements, so a building pursuing Passive House certification can't rely on "close enough" envelope detailing the way a conventional project sometimes can.
On a real project
A multifamily developer pursuing Passive House certification requires a mid-construction blower-door test specifically to catch air leakage while the envelope is still accessible for repair, rather than waiting for the final test after finishes are complete.
Who this matters most to
A Carpenter installs the continuous, carefully detailed air barrier and insulation Passive House depends on. A Sustainability/LEED Consultant manages the certification process and required testing.
Where this goes wrong
A project targeting Passive House certification waits until the building is fully finished to conduct its first blower-door test, discovering the envelope falls well short of the required airtightness. With finishes already installed, tracking down and sealing the source of the leakage becomes far more disruptive and expensive than it would have been during rough framing.