About 475

475 High Performance Building Supply (475) provides essential building knowledge and components to building professionals.

475 helps make more durable, resilient, ecological, and energy-efficient buildings that optimize occupant comfort and health. We enable the building improvements required to dramatically reduce our energy demand and address our climate crisis. We are an ecommerce-based catalyst in the transformation of US construction to high-performance, low-energy and Passive House buildings. The name “475” is a reference to the heat demand requirement of the Passive House Standard, 4.75 kilo BTUs per square foot per year. Passive House is the gold standard for high performance construction today.

What is Passive House?  Passive House is an international building standard that results in a roughly 90% reduction in heating and cooling energy usage and up to a 75% reduction in primary energy usage from existing building stock while making a more comfortable, healthy and affordable built environment.  Passive House optimizes passive elements like orientation, massing, insulation, airtightness, heat recovery, passive use of solar energy, solar shading, elimination of thermal bridges, and internal heat sources. The term ‘Passive House’ may also refer to a building that has been tested and certified to meet the Passive House standard – developed by the Passive House Institute in Germany.

>>Read more about Passive House

Our focus starts at airtightness – the single most important factor in building thermal performance. Proper application of tapes, membranes, and air sealing gaskets make airtight construction simple yet robust. In addition to presenting at conferences, we publish videos, details, writings, and other aids that help industry practitioners better understand the philosophy and practice of building airtightness.


Why focus on airtightness? Airtightness is more important than thermal insulation in providing a comfortable and energy efficient building. Airtightness is also a prerequisite for ensuring high indoor air quality and to provide robust protection of the building structure from moisture damage. >>Read more about airtightness on the 475 Blog.





Following airtightness, 475 focuses on related components such as high-efficiency ventilation, ecological insulation, triple-pane roof openings, and Passive House energy balance software – all complementary and essential elements in making high-performance buildings. At www.foursevenfive.com we provide professionals and the public with the necessary information to make the appropriate purchases.

475 is the Future of Green Building

Green building is a rapidly growing segment of the construction market. Green homes are expected to account for a third of the annual $100 billion residential construction market in the coming years and almost 50% of the annual $300 billion non-residential market.


Within the green building sector there is a sub-sector of high-performance, low-energy and Passive House buildings. These buildings not only strive to minimize the ecological impact of construction materials and processes, but also to yield substantial operational energy savings over the life of the building. They play an important role in addressing the need to decarbonize our economies and mitigate the problems of runaway climate change.


If green buildings are built with recycled and non-toxic materials but don’t achieve significant energy efficiencies, then they have fallen far short of green building’s promise. However, there are a growing number of practitioners acknowledging this deficit, and they are looking for help.
Focused on the knowledge and components that begin with airtightness, 475 has placed itself at the vanguard of helping industry to fulfill the promise of green building.

475 Advantage


Founded and directed by architects, 475 is a trusted source for essential building knowledge and components for the U.S. design and construction industries, as 475 provides in-depth information transparently while delivering on its promises. Key tools of 475’s efforts include:

  • Knowledge-based solutions
  • Highly specialized focus
  •  Peer-to-peer communication
  • Exclusive offerings to the U.S. of “best in class” German products
  • Web-based business-to-business interface
  • Timely product delivery from regional fulfillment centers
  • Intense attention to customer service with local on-the-ground support

The 475 monthly newsletter delivers useful and cogent technical information. Customers can download comprehensive airtightness construction details from the 475 website. The 475 blog offers specialized building science information to all readers, and constitutes a growing reference library that is accessible to all.


475 Beginnings

475 began in a conversation between Ken Levenson and Floris Keverling Buisman after completing a blower door test on a Passive House retrofit project in Westport, CT. Driving back to Brooklyn, Ken, a registered New York architect since 1993, and Floris, a Dutch trained architect and building science consultant, discussed their realization that the U.S. building supply industry didn’t seem to care much about low-energy/high-performance building or about providing the products and knowledge support required for it. By the time they crossed the Kosciuszko Bridge, they had concluded that not only did the US construction market need such high-performance materials and the knowledge to support them, but that they could do it themselves. Since founding the company in 2011, the company has grown rapidly and helped their growing base of contractors, architects and insulation installers successfully build airtight, well ventilated high performance projects all over the USA.