Performance Standards: Passive House Institute US

What is Passive House?

More Comfort, Less Energy

The Passive House Institute US (PHIUS) is a 501c(3) nonprofit organization that provides training, education, and research to promote the Passive House Building Energy standard, as well as the design approach and techniques to accomplish that standard.

Passive house is a set of design principles to create energy-efficient, comfortable buildings. Historically, it grew from an ambition to use passive techniques to make heating bills low and space heating systems small.

There are five basic principles:

  1. Employs continuous insulation throughout its entire envelope without any thermal bridging.
  2. Creates an extremely airtight building envelope, preventing infiltration of outside air and loss of conditioned air.
  3. Uses some form of balanced heat-and moisture-recovery ventilation.
  4. Employs high-performance windows (double or triple-paned) and doors – solar gain is managed to exploit the sun’s energy for heating purposes in the heating season and to minimize overheating during the cooling season.
  5. Uses a minimal heating and cooling system.

These principles can be applied to all buildings, including single-family homes, multifamily apartment buildings, schools, skyscrapers, and more. To reflect the principles’ suitability for many different building types, Phius uses the term “passive building” to refer to the passive house strategy. When it comes to designing and constructing passive buildings, cost optimization, and climate specificity are central to Phius building standards; different types of buildings in varying climate zones have distinct, optimal design strategies.

What Comprises a “Passive House” Window?

High-performance windows are an integral part of passive buildings. They must:

  • Offer clear, unobstructed views to the outside.
  • Provide natural light, but also permit the optimal amount of heat from the sun to enter the building.
  • Seal against wind and precipitation.
  • Open if desired but be as airtight as possible when closed.
  • Reduce energy loss by keeping the heat in during the winter and out during the summer.
  • Last for decades to ensure the building performs as expected.

About Phius

A leader in the passive building space, Phius trains and certifies professionals, maintains the Phius climate-specific passive building standard, certifies and quality assures passive buildings, certifies high-performance building products, and conducts research to advance high-performance buildings.

Phius climate-specific, cost-optimized passive building standards are applicable to any building type and guide designers and builders to success worldwide. They provide a quality-and-conservation-first framework for net zero building. Phius standards are internationally applicable, grounded in building science, based on best practices, and backed by strict quality assurance to deliver optimal results. Visit to learn how you can build more comfortable, healthy, cost-efficient buildings.

About Us

provides unbiased information and education to the public on the energy efficiency, technical, and human considerations that influence window selection and use. The EWC collaborates with allied organizations, educational institutions, and government agencies that promote energy efficiency in residential windows. We do not sell, service, install, or recommend products, or endorse manufacturers. Descriptions and specifications of the products in the Window Selection Tool are provided by the manufacturer. The EWC is not liable for any manufacturing defects or inaccurate product descriptions and specifications and does not guarantee the performance of NFRC-certified windows, doors, and skylights.

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