ASHRAE 62.2 Explained | How to Calculate Home Ventilation, CFM & Indoor Air Quality

Learn ASHRAE 62.2 residential ventilation from start to finish, including how ventilation requirements are calculated, how actual airflow is tested, how blower door results may affect infiltration credit, and how proper ventilation supports indoor air quality, moisture control, comfort, health, and building performance. ASHRAE Standard 62.2 establishes residential ventilation and indoor-air-quality requirements for dwelling units. For energy auditors, HVAC contractors, weatherization professionals, HERS raters, builders, and home-performance contractors, understanding this standard is critical when working with tighter, more energy-efficient homes. This video explains: ✓ What ASHRAE 62.2 means ✓ Whole-dwelling ventilation requirements ✓ Conditioned floor area and bedroom calculations ✓ Ventilation CFM calculations ✓ Qtot and mechanical ventilation concepts ✓ Blower door testing and infiltration credit ✓ CFM50 and envelope leakage ✓ Exhaust-only ventilation ✓ Supply-only ventilation ✓ Balanced ventilation systems ✓ HRVs and ERVs ✓ Kitchen exhaust requirements ✓ Bathroom and local exhaust ventilation ✓ Measuring actual installed airflow ✓ Why fan-rated CFM may differ from measured CFM ✓ Ventilation commissioning ✓ Filtration and MERV requirements ✓ Moisture and humidity control ✓ Carbon monoxide and combustion-safety considerations ✓ Weatherization test-in and test-out procedures ✓ Indoor air quality and occupant health ✓ Professional ventilation documentation Example Ventilation Calculation A commonly encountered recent-edition calculation concept is: Qtot = 0.03 × Conditioned Floor Area + 7.5 × (Bedrooms + 1) For a 2,000 sq. ft., 3-bedroom home: 0.03 × 2,000 = 60 CFM 7.5 × 4 = 30 CFM Total = 90 CFM Always verify the exact ASHRAE 62.2 edition adopted by the applicable jurisdiction, energy code, weatherization program, utility, or project, because formulas, credits, exceptions, and requirements can vary by edition. Measure—Don’t Assume If a ventilation fan is rated at 80 CFM but delivers only 58 CFM after installation, the system is not delivering 80 CFM. Duct resistance, elbows, restrictive terminations, poor installation, incorrect fan settings, and other factors can reduce actual airflow. Professional commissioning means: Calculate → Install → Measure → Correct → Verify → Document Why ASHRAE 62.2 Matters As homes become tighter through air sealing, insulation, better windows, duct sealing, and energy-efficiency improvements, uncontrolled air leakage decreases. That is good for energy performance—but tighter homes need intentional ventilation. The goal is not simply to move more air. The goal is to provide controlled, appropriate, measured ventilation while managing pollutants, moisture, filtration, comfort, energy use, and building pressure. Air Seal Tight. Ventilate Right. Verify the Airflow. With BPMS™ — Building Performance Modeling Systems, professionals can connect building area, bedroom information, blower door testing, ventilation equipment, measured airflow, field photographs, HVAC information, indoor-air-quality observations, and professional reporting within the broader building-performance workflow. BPMSField™ can help document ventilation equipment, controls, ducts, exhaust systems, terminations, and field evidence directly at the property. BPMS Intelligence™ can assist with identifying missing or inconsistent project information while the qualified professional remains responsible for selecting the correct standard, performing calculations, measuring airflow, and approving the final result. BPMS™ — One Platform. Complete Building Performance. Explore BPMS™ at BPMSCloud.com

Originally uploaded October 7, 2026