Page 3
1. VENTILATION REQUIREMENTS
DETERMINE YOUR
VENTILATION NEEDS
INSTALLATION
How much fresh air do I need? Good air
quality is based in part on the capacity
of the home’s ventilation system.
Usually, the HRV’s/ERV’s capacity
is measured in CFM (Cubic Feet per
Minutes) or L/s (Liters per Seconds) of
fresh air being distributed in the living
space. The Room Count Calculation or
the Air Change per Hour Method shows
you how to determine your ventilation
needs. (see chart on right)
A. Room Count Calculation
LIVING SPACE
NUMBER OF ROOMS
CFM (L/S)
CFM REQUIRED
Master Bedroom
————
x 20 cfm (10 L/s)
=
————
With Basement
————
x 20 cfm (10 L/s)
=
————
Single Bedroom
————
x 10 cfm (5 L/s)
=
————
Living Room
————
x 10 cfm (5 L/s)
=
————
Dinning Room
————
x 10 cfm (5 L/s)
=
————
Family Room
————
x 10 cfm (5 L/s)
=
————
Recreation Room
————
x 10 cfm (5 L/s)
=
————
Other
————
x 10 cfm (5 L/s)
=
————
Kitchen
————
x 10 cfm (5 L/s)
=
————
Bathroom
————
x 10 cfm (5 L/s)
=
————
Laundry Room
————
x 10 cfm (5 L/s)
=
————
Utility Room
————
x 10 cfm (5 L/s)
=
————
TOTAL ventilation requirement (add last column) =
————
1 CFM = 0.47189 L/s
1 L/s = 3.6 m3/hr
B. Air Change per Hour Method
TOTAL cu ft X 0.35 per hr = total
Take total and divide by 60 to get CFM
Example: A 25’x 40’ house with basement
1,000 Sq. ft. x 8’ high x 2(1st floor + basement) = 16,000 cu. ft.
16,000 cu. ft. x 0.35 ACH = 5,600 cu. ft.
5,600 cu. ft. / 60 Minutes = 93.3 CFM
93.3 CFM is your ventilation need
