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Airtight Windows and Indoor Air Quality

When the air outside is considered extremely dangerous to breathe, we seek refuge indoors – where we hope the air quality is better. And in high-performance homes and buildings, it can be.

The many active wildfires in California and the Pacific Northwest has resulted in unhealthy air quality as measured by the US Environmental Protection Agency’s Air Quality Index (AQI). Recently, the AQI has stagnated for many days in the 200-300 range in some areas, such as Vancouver, British Columbia, while the AQI greatly exceeded the scale’s maximum value of 500 in other areas, such as in Eugene, Oregon. As a result, the air quality in the Pacific Northwest is currently considered “very unhealthy” to “hazardous to health”, ranking it the worst in the world.

Pacific Northwest Air Quality

Source: https://gispub.epa.gov/airnow/

And while we may not be able to control (that is not to say we don’t affect) the outside air, the good news is that we do have the knowledge and technology to control the inside air so that we can stay healthy indoors.

A high-performance home or building, such as one built to the Passive House Standard, benefits from an extremely airtight building envelope and complementary high-efficiency mechanical and advanced air filtration systems. Together, these provide much greater control of the quality of the air inside a home or building, making it a treasured haven when the outside air quality takes a dive.

Windows and Doors with Superior Airtightness

Experienced high-performance building professionals understand the importance of an airtight building envelope. And windows and doors significantly impact the airtightness of the building envelope.

BuiltGreen Platinum certified home by Lentel Construction. This home achieved an impressive 0.31 ACH50 on its final blower door test.

Innotech windows and doors are engineered and manufactured to deliver superior airtightness, as tested, rated and labelled in accordance with the North American Fenestration Standard/Specification (NAFS).

Here are the NAFS airtightness results for some of our standard windows and doors:

The Air Leakage Resistance test was performed in accordance with ASTM E283-04(2012), “Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen”. Air infiltration and exfiltration tests were performed using test pressures of 75 Pa (1.57 psf).

In addition to the required NAFS testing, we conduct regular in-house and on-site air leakage testing. It is our ongoing commitment to superior performance that has allowed us to continually refine our windows and doors over twenty years to deliver outstanding performance – including airtightness.

While the overall system of our windows and doors is designed to be airtight, there are two components that contribute the most to superior airtightness: triple weather seals and operating hardware.

Triple Weather Seals 

Operable windows and doors have seals, also known as gaskets or weather seals, to seal the window and door from air penetration. A high-performance window and door must have a superior sealing system.

Our windows and doors have three high-quality, flexible and continuous seals. The first seal is located on the exterior of the frame, the second seal is located on the interior of the frame and third seal located in the center of the frame. This center seal is a continuous seal with heat-welded corners that is exactly positioned to improve the seal as the air pressure on the window increases. It also protects the operating hardware from corrosive exterior air and improves the thermal performance by dividing the sash-to-frame gap in two to reduce convection.

The third seal in our Defender 76TS System provides an additional line of defense against air, water and sound.

Multipoint Locking & Adjustable Operating Hardware

For operable windows and all doors, the operating mechanism is a critical component to resist air infiltration and exfiltration.

Every Innotech Tilt +Turn Window and exterior door has a band of steel on the sash that securely bolts to the frame at multiple points: sides, top and bottom. The number of locks and the spacing of these locks varies depending on the size of the product. When locked, the multipoint hardware tightly compresses the seal on the frame by engaging each locks on the sash. The result is an airtight, watertight and sound resistant seal on all four sides of the window and door.

Our operating hardware is also fully adjustable and easy to replace. The locks are not only adjustable up, down, left and right, but the locking pressure is also adjustable. The ability to adjust and replace the operating hardware ensures your windows and doors can do their job – prevent air, water, and sound from entering – for many decades.

The recent state of our air quality highlights the importance of designing and building to high-performance standards. When the right building materials and technologies are chosen, such as airtight windows and doors, the result is a healthy, comfortable and durable home.