Frequently Asked Questions (FAQ)

ASHRAE 62.2 Standard

  • How is the height of a dwelling measured?
    The vertical distance between the lowest and highest above-grade points within the dwelling pressure boundary. This height should include the above-grade part of a basement if the basement is within the pressure envelope. Do not include an attic if it is not within the pressure envelope.

  • May I claim an infiltration credit for multifamily dwelling units?

    For ASHRAE 62.2-2016 you may claim an infiltration credit for horizontally attached dwelling units in a multifamily building, but not for dwelling units that are one above the other (stacked). For ASHRAE 62.2 versions before 2016, you may not claim an infiltration credit for ANY dwelling unit in a multifamily building.

    The horizontally attached infiltration credit is a partial credit based on the ratio of the area of the exterior surfaces NOT connected to other dwelling units to the total surface area. For example, if the exterior surface area not connected to other dwelling units is 2400 square feet and the surface area common to the adjacent unit(s) is 600 square feet, the total surface area is 3000 square feet. So you may claim 80% of the full infiltration credit (2400/3000 = 0.8). If the blower door test result for this horizontally attached dwelling unit it 1600 CFM50, the allowed credit is 1600 x 0.8 = 1280 CFM50.

  • How often is the ASHRAE 62.2 Standard officially updated?

    The 62.2 Standard is updated every three years. It was first published in 2003, then in 2004, 2007, 2010, 2013, 2016, 2019, and 2022. Intermittent versions are sometimes published by ASHRAE between the years of the full edition.

  • What is the official title of the ASHRAE 62.2 Standard?
    The full title of the Standard is Ventilation and Acceptable Indoor Air Quality in Residential Buildings. The Standard covers single-family detached dwellings, manufactured homes, and multifamily buildings of any size (dwelling units only; ASHRAE 62.1 covers the non-dwelling spaces in multifamily buildings). The ASHRAE 62.2 Standard is available for purchase at the ASHRAE website. It may also be read free-of-charge at the ASHRAE website.

  • What types of mechanical ventilation are required by the ASHRAE 62.2 Standard?

    The types of mechanical ventilation include:

    • Local ventilation is intended to exhaust airborne contaminants at their source.
      • Full bathrooms
        • 50 CFM (25 L/s) for demand-controlled exhaust.
        • 20 CFM (10 L/s) exhaust if operated continuously.
      • Kitchens
        • 100 CFM (50 L/s) demand-controlled exhaust if the range hood is installed directly over a range, or 300 CFM (150 L/s) if not directly over the range.
        • 5 air changes per hour continuous exhaust ventilation if the kitchen is “enclosed”. An enclosed kitchen is defined as a kitchen whose permanent openings to interior adjacent spaces do not exceed a total of 60 square feet (6 square meters).
    • Dwelling-unit ventilation is intended to serve as dilution ventilation. In older versions of ASHRAE 62.2, this is termed “whole-house” or “whole-building” ventilation.
      • The CFM (L/s) minimum requirement is based on 1) the area of the living area and the number of occupants (bedrooms).
        • The minimum requirement for fresh outdoor air is supplied by natural air leakage (infiltration) and mechanical ventilation (exhaust, supply, or balanced).
  • If I install a balanced ventilation system, sometimes referred to as a Heat Recovery Ventilation (HRV) or Energy Recovery Ventilation (ERV), may I add the exhaust airflow and supply airflow together for compliance with the ASHRAE 62.2 Standard?
    No, the exhaust and supply airflows are not added together. For example, if the minimum dwelling-unit ventilation requirement if 100 CFM (50 L/s), the balanced ventilation system must supply 100 CFM (50 L/s) and exhaust 100 CFM (50 L/s).