Blower door tests: Learn the basics

What is a blower door test and why would you need one? Here’s a summary of what you need to know about this performance-based metric for buildings.

What is a blower door test?

A blower door test is a machine used to calculate airflow between the interior and exterior of a structure, measure the airtightness of buildings, and identify spots where air is leaking through a building envelope. This test ensures a certain level of energy performance and is often used when a project team is aiming for a performance-based building standard like Passive House, which requires a blower door test result of less than 0.6 air changes per hour at 50 pascals of pressure (ACH 50).

blower door machine

Blower door test equipment

A blower door machine consists of a fan that can induce various airflows to pressurize and depressurize the building, a tool to measure pressure, and a mount to secure the fan in a rough opening such as a door or window.

What is Passive House?

Passive House is a building standard with extremely rigorous energy performance requirements. Passive House design principles include airtight construction, continuous insulation, minimized thermal bridging, energy recovery ventilation, and solar optimization. This standard mandates a blower door test result of less than 0.6 ACH50.

To learn more about Passive House, visit the Passive House Institute US (PHIUS) website, or the North American Passive House Network (NAPHN) website.

How can R-Guard help me achieve Passive House?

Since becoming the first fluid-applied air barrier on the market nearly 20 years ago, R-Guard air and water barriers have helped myriad construction professionals meet and exceed their energy performance goals, including some of the world’s most ambitious building standards Passive House, Living Building Challenge, and Net Zero. The fluid-applied silyl-terminated polymer (STP) system creates a monolithic barrier that keeps air and water out, but is also permeable to allow buildings to breathe. The combination of R-Guard advantages promotes enduring performance even during building movement and changing climate conditions.

Is R-Guard difficult to install?

The R-Guard system was first designed by contractors who needed a top-performing air and water barrier, and ease of application was one of the most important traits they required.

Their list of traits quickly grew to include 13 product attributes, including the ability to save time, adhere to different materials without a primer, and be immediately waterproof.

The result of this “wish list” is the R-Guard system of products, including Joint & Seam Filler, FastFlash, Cat 5 and AirDam. This system can be installed in less time and contributes to greater long-term energy efficiency than alternative products. R-Guard products also adhere to almost all types of construction materials, simplifying the installation process.


Karuna House R-Guard application

Air & Water Barriers

In pursuit of Passive

Part of PROSOCO's Guide to Blower Door Testing BLOWER-DOOR TEST PASSED ON ATTEMPT #1 Rainy weather was rendered a non-factor for Oregon’s Karuna House, causing zero delays as the crew used a fluid-applied air barrier on damp plywood. The air barrier installation on this Passive House residential project went faster[…]


Exceeding Passive House

Homeowners beat Passive House standard by more than half

The team at Heritage Window & Door confidently recommended R-Guard by PROSOCO to help meet their aggressive air tightness target for their new 4,000-square-foot home.

Palm trees in hurricane

Air & Water Barriers

The case for FastFlash and Passive Houses

When we introduced the PROSOCO R-Guard FastFlash air and waterproof barrier system, we knew a big market would be in coastal areas subject to tropical storms and hurricanes. That's because FastFlash is tested and proven to stop air and water leaks through building envelopes in conditions up to and exceeding[…]



The Bullitt Center and the transformation of building materials

The six-story, 50,000 square foot Bullitt Center is seeking to change how buildings are designed, built and operated. Its goal: to shift the benchmarks significantly forward for long-term environmental performance and energy efficiency, renewable energy and other green building technologies. Seattle's Bullitt Center seeks to be a "living building" --[…]