Passive House

Passive House, known in German as Passivhaus, is a voluntary building performance standard that achieves extremely low heating and cooling energy demand through building design rather than mechanical systems alone. Developed in Germany in the late 1980s and formalized by the Passivhaus Institut in 1996, the standard has since been adopted worldwide for homes, offices, and schools, and typically cuts heating and cooling energy use by 75 to 90 percent compared to conventional new construction.

The standard rests on five core principles working together: superinsulation of walls, roof, and foundation well beyond typical building codes; elimination of thermal bridges (points where heat can bypass insulation); an extremely airtight building envelope, verified by a blower-door test; high-performance triple-pane windows; and continuous heat-recovery ventilation that brings in fresh air while capturing most of the heat that would otherwise be lost. Because the insulation and airtightness work is central to hitting Passive House targets, the Insulation Calculator is a useful companion tool for estimating how much added insulation reduces heat loss on a specific building.

Passive House buildings are often paired with on-site renewable generation and Net Metering arrangements to approach or achieve net-zero energy status, since their dramatically reduced energy demand makes it far easier for solar panels to cover the remaining load. The Passive House Savings Calculator estimates the annual energy and cost savings a specific home could achieve by meeting the standard, compared to conventional construction.

• Certification requires meeting strict numeric targets: A building must demonstrate space heating demand at or below 15 kilowatt-hours per square meter per year, total primary energy demand below a set threshold, and airtightness of no more than 0.6 air changes per hour at 50 pascals pressure difference — verified by third-party testing, not just design intent.
• Passive House differs from Net Zero and LEED: Passive House is an envelope-and-ventilation performance standard, while Net Metering-enabled net-zero status depends on pairing efficiency with on-site generation, and LEED evaluates a much broader set of sustainability criteria beyond energy alone — a building can pursue one, two, or all three.
• Insulation is the foundation, not an afterthought: Because Passive House heating targets are so low, wall, roof, and foundation insulation levels are typically two to three times thicker than standard code minimums — the Insulation Calculator helps quantify the heat-loss reduction from specific insulation upgrades during design or retrofit planning.
• Airtightness demands mechanical ventilation: An extremely airtight envelope eliminates uncontrolled drafts but also removes natural fresh-air exchange, making heat-recovery ventilation systems (HRV/ERV) a mandatory, not optional, component of every certified Passive House.
• Retrofits use a relaxed standard called EnerPHit: Existing buildings, especially those with historic facades or space constraints, can pursue EnerPHit certification, which applies somewhat less strict targets than new construction while still delivering most of the energy savings of a full Passive House.