Recently, I had the pleasure of conducting a blower door test for Allan Hocking’s Passivhaus project in Ascot. The blower door test is essential for assessing the air tightness of a building, and this test yielded remarkable results that underscored Allan’s dedication to high-quality construction. Achieving airtightness at such a high level means improved energy efficiency, comfort, and durability, all while meeting Passivhaus standards.
The blower door test measures air changes per hour at 50 Pascals (ACH50), essentially telling us how much air leaks in or out of the house when subjected to a specific pressure. For a home to meet the stringent Passivhaus standard, it must achieve a result of 0.6 ACH50 or below. This ensures minimal heat loss and exceptional energy efficiency, which are key goals for a Passivhaus build.
The test at Allan’s Ascot property yielded an impressive result of 0.21 ACH50, well below the Passivhaus limit. Not only did this score pass the Passivhaus requirements, but it also set a new benchmark in my testing experience; 0.21 ACH50 is the lowest score I have ever recorded. This extraordinary level of airtightness is a testament to Allan’s precision and craftsmanship.
Allan, a certified Passivhaus tradesperson, constructed this home using the principles and methods of Passivhaus, including meticulous sealing and layering of insulation to avoid thermal bridging. Such attention to detail doesn’t just contribute to energy efficiency; it also improves indoor air quality and comfort by reducing drafts and maintaining stable temperatures.
Beyond the Passivhaus certification, I assessed Allan’s build through Gold Star method, which I use to evaluate compliance for building permit purposes as well as to recognize quality in energy-efficient builds. My Gold Star Premium certificate is awarded only when a build meets or exceeds specific high-performance criteria. Due to Allan’s exceptional result and adherence to best practices, I awarded him the very first Gold Star Premium certificate—a recognition of both his technical skill and his dedication to high performance construction.
Achieving 0.21 ACH50 means Allan’s Passivhaus will use a fraction of the energy that a conventional home would need to stay comfortable year-round. Homeowners in Passivhaus-certified builds like Allan’s benefit from significantly lower energy bills and greater levels of comfort.
For builders and homeowners considering Passivhaus or other high-performance building standards such as Gold Star, Allan’s project is an inspiring example of what is possible with careful planning and craftsmanship. This level of performance is about more than just meeting a standard; it’s about building homes that are truly resilient, healthy, comfortable, durable, and energy efficient.
Blower door tests are an invaluable tool in gauging the success of these builds, which is why I include them in my Gold Star system. A low ACH50 score reflects the effectiveness of materials, techniques, and a builder’s dedication. Allan’s 0.21 ACH50 score at Ascot shows that the bar for energy-efficient construction keeps rising, and with knowledgeable builders like Allan Hocking, the future of high performance building looks bright.
