Calculate required outdoor air ventilation rates per ASHRAE 62.2 (residential) and 62.1 (commercial). People-based and area-based outdoor air requirements for any space type.
Size Heat Recovery Ventilators (HRV) for residential and commercial applications. Calculate required airflow, heat recovery efficiency, and annual energy savings vs. exhaust-only ventilation.
Size Energy Recovery Ventilators (ERV) with both sensible and latent energy recovery. Calculate total energy savings and determine if HRV or ERV is more appropriate for your climate.
Calculate air changes per hour for any space from airflow rate and room volume. Verify against ASHRAE minimum ACH requirements for different space types.
Calculate indoor CO₂ concentration from occupancy, outdoor air supply, and metabolic activity. Verify against ASHRAE 62.1 IAQ limits (1000 ppm max) and determine required OA flow.
Size bathroom, kitchen, laundry, and whole-house exhaust fans per HVI and ASHRAE 62.2 requirements. Calculate required CFM based on room size and usage frequency.
Calculate minimum outdoor air quantities per ASHRAE 62.1 Ventilation Rate Procedure for multiple zones. Includes zone diversity factor and system outdoor air efficiency.
Size commercial kitchen exhaust hoods and makeup air systems. Calculate exhaust CFM from hood type, cooking equipment, and duty — per ASHRAE 154 and NFPA 96.
Calculate required makeup air for spaces with large exhaust systems. Prevent negative pressure that causes backdrafting of combustion appliances and door pressure problems.
Calculate natural ventilation airflow through windows and openings from wind speed, direction, and pressure coefficients per ASHRAE Handbook of Fundamentals.
Assess overall indoor air quality from ventilation rates, pollutant sources, and occupancy. Calculate dilution ventilation required to maintain acceptable pollutant concentrations.
Calculate sensible and latent heating and cooling loads from mechanical ventilation. Compare loads with and without HRV/ERV to justify energy recovery investment.
Size garage ventilation systems for CO and combustion gases. Calculate required ACH and fan capacity per ASHRAE and NBC requirements for attached and detached garages.
Calculate supply vs. return imbalance needed to maintain positive or negative pressure in a space. Used for isolation rooms, clean rooms, and pressure-sensitive applications.
Verify commercial ventilation systems against the ASHRAE 62.1 Ventilation Rate Procedure. Calculate zone and system outdoor air with occupancy diversity and zone air distribution effectiveness.
Check whether your HRV or ERV stays balanced once bathroom fans, the range hood, and the dryer are running, and whether you need dedicated makeup air.
Size a bathroom exhaust fan by floor area or fixture count, with intermittent and continuous rates and a recommended sone rating.
Calculate and compare the ASHRAE 62.1 people outdoor air rate (Rp) by occupancy category, from office to gym to classroom.
Calculate air changes per hour and supply airflow for ISO Class 5 through Class 8 clean rooms, with pressure cascade guidance.
Calculate CO2-based demand-controlled ventilation setpoints and minimum outdoor air rates per ASHRAE 62.1. Estimate energy savings against a fixed-rate ventilation baseline.
Calculate the dilution airflow needed to keep an airborne contaminant below its target concentration. Useful for general exhaust ventilation where source capture isn't practical.
Calculate air changes per hour and pressure relationships for hospital spaces per CSA Z317.2 and ASHRAE 170. Covers operating rooms, isolation rooms, and patient wards.
Calculate uncontrolled air leakage through the building envelope from blower door results or the ASHRAE infiltration estimation method. Convert the result to a heating and cooling load.
Calculate exhaust airflow and air changes per hour for laboratory spaces with fume hoods. Verify the makeup air balance and pressure relationship to adjacent corridors.
Size localized spot exhaust for workstations, equipment, and point sources of contaminants. Calculate capture velocity and hood airflow for effective contaminant removal.
Calculate air transferred between adjacent zones to support exhaust-heavy spaces like bathrooms and kitchens without dedicated makeup air. Confirm the donor room stays in balance.
Calculate the heating and cooling energy recovered by an HRV or ERV compared to exhaust-only ventilation. Estimate annual energy and cost savings for your climate zone.
Calculate the continuous whole-house mechanical ventilation rate required under ASHRAE 62.2 and the National Building Code. Compare exhaust-only, supply-only, and balanced strategies.
Calculate the Air Quality Health Index from PM2.5, ozone, and NO2 concentrations using Environment Canada's AQHI methodology. Get a risk category and ventilation recommendation.
Calculate minimum outdoor air using the ASHRAE 62.1 IAQ Procedure based on contaminant source strength and target concentration. Compare results against the standard Ventilation Rate Procedure.
About Ventilation & IAQ Calculations
Proper ventilation is fundamental to indoor air quality, occupant health, and building durability. In Canada, as buildings have become increasingly airtight under NBC requirements, mechanical ventilation has become mandatory rather than optional. These tools help design and verify ventilation systems that meet ASHRAE 62.1 (commercial) and ASHRAE 62.2 (residential) requirements.
ASHRAE 62.2 — Residential Ventilation
ASHRAE 62.2 defines minimum mechanical ventilation requirements for low-rise residential buildings. The whole-building ventilation rate is calculated as: Qfan = 0.01 × Afloor + 7.5 × (Nbr + 1) CFM, where Afloor is floor area in ft² and Nbr is the number of bedrooms. In Canadian homes, this is typically provided by an HRV or ERV integrated with the forced-air system. Use the Ventilation Rate Calculator for precise requirements.
HRV vs ERV — Which is Right?
Heat Recovery Ventilators (HRV) recover sensible heat only — ideal for most Canadian climates where winter humidity control is important. Energy Recovery Ventilators (ERV) recover both heat and moisture — better suited for hot-humid climates where summer dehumidification is the primary concern. In most Canadian provinces, HRV is the standard recommendation. Use the HRV Calculator and ERV Calculator to size the right system.
Related Tools
Ventilation loads connect directly to heat load calculations and cooling load calculations. The infiltration load calculator addresses the uncontrolled side of air exchange, while these tools handle the mechanical ventilation side. See also Air Quality tools for detailed pollutant and IAQ analysis.