Reflecting on the Origins of Airtightness Testing with Harold Orr

Reflecting on the Origins of Airtightness Testing with Harold Orr

Watch the full episode of The FlowLab podcast, where we dive deeper
into Harold’s stories and explore the future of airtightness testing.

At Retrotec, we have always been passionate about innovation in airtightness testing, which is why it was an absolute privilege to sit down with one of the pioneers of this field, Harold Orr, for an insightful episode of the FlowLab podcast. Now 92 years old, Harold shared fascinating stories from his decades-long journey in building science and construction. His experiences have not only shaped the air-tightness industry but continue to influence how we think about energy efficiency today.

A Lifetime of Innovation Harold Orr’s career began early—he started doing carpentry work at the age of 12 in 1943, helping his father build a house. His passion for construction led him to pursue mechanical engineering at the University of Saskatchewan. From there, Harold’s path to becoming a pioneer in airtightness testing was set. His pivotal work began in the early 1960s when he addressed a major challenge in construction: accurately measuring heat loss due to air leakage in buildings.

Back then, the methodology for determining air leakage was crude at best. Builders often relied on incomplete measures or simply doubled their calculated heat loss through walls and ceilings to estimate air leakage. Orr’s curiosity and determination led him to create an early tracer gas system, injecting helium into buildings to measure how fast it leaked out. Despite early setbacks, including a non-functional thesis prototype, Harold’s perseverance paid off as he refined his work with the National Research Council, making significant advances in airtightness testing.

The Birth of the Blower Door In the 1970s, Harold designed the original version of the blower door, which has since become an essential tool in the construction and energy-efficiency industries. His early designs, using surplus fans from aircraft and homemade pressure measurement devices, may seem primitive by today’s standards, but they were groundbreaking at the time. The idea of depressurizing a building to measure air leakage was revolutionary, and it laid the foundation for the airtightness testing industry as we know it.

Harold’s work directly inspired the development of the blower door, now widely used across the industry. It’s incredible to think that a simple plywood door and a fan could evolve into the sophisticated tools we use today to ensure energy efficiency and airtightness in modern homes.

A Lasting Legacy One of the highlights of our conversation was hearing about the Saskatchewan Conservation House, a project that Harold worked on in response to the 1970s oil crisis. Built to withstand Saskatchewan’s harsh climate, this house set the standard for airtight construction, achieving an impressive 0.5 air changes per hour at 50 pascals of pressure. This level of airtightness directly influenced the Passive House movement in Europe, which continues to set the global benchmark for energy-efficient buildings. The house had nearly 1,000 visitors per week while it was open.

Harold’s legacy doesn’t stop there. His work has shaped not only the technology we use at Retrotec but also the way we think about energy efficiency in general. As Harold pointed out during our discussion, “If cars can be airtight, so can houses.” His belief in the importance of airtightness and proper ventilation remains a core principle in the construction industry today.

Moving Forward As we continue to innovate at Retrotec, it’s essential to reflect on the pioneers like Harold Orr, whose work laid the foundation for so much of what we do. His story reminds us that perseverance, curiosity, and a willingness to challenge the status quo can lead to groundbreaking advancements. We are honored to have had the opportunity to hear Harold’s firsthand account of the origins of airtightness testing, and we look forward to continuing his legacy of innovation.

The Flow Lab Podcast by Retrotec

Retrotec has launched The Flow Lab podcast to connect you with the leading minds within the building science industry.  We interview everyone from long-time experts to the newest innovators, exploring the latest technology advancements and industry news.  Subscribe on the Retrotec YouTube channel and wherever you listen to podcasts.  Like and subscribe to become part of the Flow Lab community!