Determine Your EVR/HRV Ventilation System Needs
How much fresh air do you need?
Good air quality is based in part on the capacity of the home’s ventilation system. Usually, the unit’s capacity is measured in CFM (cubic feet per minute) or L/s (liters per second) of fresh air being distributed in the living space. Use the ASHRAE 62.2 Ventilation Standard, the Room Count Calculation Method, or the Air Change per Hour (ACH) Method to determine your ventilation needs:
ASHRAE 62.2 Ventilation Standard
Room Count Calculation Method
Air Change Per Hour (ACH) Method
Total cubic feet x 0.35 per hour = total cubic feet hour
Take total and divide by 60 to determine cubic feet per minute (CFM)
Example:
- 25ft x 40ft (1,000sq ft) house with basement
- 1,000sq ft. x 8ft high x 2 (1st floor + basement) = 16,000 cu. Ft
- 16,000 cu. ft. x 0.35 ACH = 5,600 cubic feet per hour
- 5,600 cu ft. / 60 minutes = 93 cubic feet per minute (CFM)
- 93 CFM is your ventilation need