Indoor Air Quality (IAQ) Calculator

Calculate ventilation requirements and CO2 levels per ASHRAE 62.1

Total volume of the occupied space in cubic feet. Length × width × ceiling height.
cu ft
Maximum expected occupancy for the space. Use design occupancy, not average.
ASHRAE 62.1 requires 15-20 CFM/person for offices, 5-7.5 for retail spaces.
CFM/person
Sedentary adult ~0.31 CFH. Light activity ~0.39, moderate ~0.55 CFH of CO2.
CFH/person
Typical outdoor CO2 is 380-420 ppm. Urban areas may be higher.
ppm

Results

Required Outdoor AirCFM
Steady-State CO2ppm
Air Changes per HourACH
ASHRAE 62.1 Compliance
References: ASHRAE Standard 62.1 — Ventilation for Acceptable Indoor Air Quality. CO2 above 1000 ppm indicates inadequate ventilation. Target is 600-800 ppm above outdoor levels.