A tighter home means:

• Lower heating costs
• More energy efficient
• Less drafty
• More comfortable

As airtightness improves, money can be saved, but proper ventilation also becomes more necessary.

Airtightness plays a large role in determining the energy efficiency and comfort level of a house. Every hole or protrusion between the interior and exterior of the building envelope should be sealed to maintain the airtightness of the home. A small hole can increase the air leakage greatly.

All rough-ins should be completed before insulating begins. Additional rough-ins and or changes after insulating can be very detrimental to the airtightness of the house. Whenever a new rough-in is added to a home, ensure all protrusions to the exterior of the home are sealed properly, and that the air barrier remains continuous.

Great care must be taken to ensure the vapour retarder and air barrier are installed correctly and that the air barrier is sealed and continuous throughout the entire home. Keep this in mind with upgrading an existing home and be sure to reseal any holes created in the existing air barrier during an upgrade.

Air Barriers and Airtightness

• Properly installed air barriers are the key to an air tight home
• Airtightness tests are performed to determine the effectiveness of the air barrier system
• There are various programs used for existing and new home assessments. Some require a specified airtightness to meet the program requirements, while others do not
• During new construction, an airtightness test (pre-test) can be performed before the dry wall is installed to check for and identify leakage areas that can easily be fixed before the drywall is installed
• The leakage areas found should be noted and those areas should be double checked on the next home being constructed

The OBC will be implementing airtightness awareness and requirements in the near future.

• Effective January 1, 2019: Air leakage testing will be mandatory (no minimum or maximum ACH at this point). There will also be a 100% requirement for continuous insulation.
• Effective January 1, 2022: There will be an air leakage requirement.