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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
