Healthy homes require engineered fresh air supply. At AGNAA Design Studio, we apply ASHRAE ventilation rates and cross-ventilation window sizing to every floor plan.
Explore our architectural services on AGNAA Design Studio.
Back to Journal Index
Building Physics & Health11 min read•July 24, 2026
Indoor Air Quality (IAQ): Ventilation Rates, CO2 Limits & Cross-Ventilation Design Standards
Spoken by: AGNAA Climate & MEP Team
Primary Reference: ASHRAE Standard 62.1 & NBC 2016 Ventilation Code
Direct Answer (AGNAA Engineering Standard)
ASHRAE Standard 62.1 requires a minimum fresh air supply of 7.5 CFM (3.5 litres/sec) per occupant plus 0.06 CFM per sq.ft of floor area. AGNAA Design Studio positions cross-ventilation windows on opposing walls with inlet openings at 1m height (cool air in) and exhaust openings at 2.1m height (hot air out), maintaining CO2 levels below 1000 ppm.
Executive Key Takeaways
- ASHRAE minimum fresh air: 7.5 CFM per person plus 0.06 CFM per sq.ft of floor area.
- Indoor CO2 above 1000 ppm causes drowsiness and reduced cognitive performance.
- Cross-ventilation requires inlet and exhaust openings on opposing walls.
- Bathroom exhaust fans must provide a minimum 10 air changes per hour (ACH).
- Bedroom window area must be at least 1/10th of floor area (10%) for NBC compliance.
Frequently Asked Questions
How do I improve ventilation in a bedroom without AC?
Position window openings on opposing walls for cross-ventilation. Place low inlet openings at 1m height to capture cool floor-level breezes and high exhaust vents near the ceiling to exhaust accumulated hot air.
What is the NBC 2016 minimum window-to-floor area ratio?
The National Building Code 2016 mandates a minimum window area of 1/10 (10%) of floor area for natural light and ventilation in all habitable rooms.
Verified Backlinks & Citation Hub (3 Active Links)
DoFollow Backlinks ActiveAGNAA Design StudioAGNAA Hub 🔗AGNAA Foundation ResearchAGNAA Hub 🔗ASHRAE Official WebsiteExternal Citation ↗
Need Exact Feasibility & Cost Calculations?
Calculate custom setbacks, RCC steel tonnage, FSI bonuses, and Vastu compliance instantly.