4
Room classification Number of rooms
CFM (L/s)
CFM Required
Master bedroom
x 10 L/s (20 CFM)
=
Basement
yes or no
=
Bedrooms
x 5 L/s (10 CFM)
=
Living room
x 5 L/s (10 CFM)
=
Others
x 5 L/s (10 CFM)
=
Kitchen
x 5 L/s (10 CFM)
=
Bathroom
x 5 L/s (10 CFM)
=
Laundry room
x 5 L/s (10 CFM)
=
Utility room
x 5 L/s (10 CFM)
=
Total Ventilation Requirements
(add last column )
=
if yes add 10 L/s (20 CFM)
if no = 0
1 CFM = 0.47 L/s
1 L/s = 2.13 CFM
Room Count Method
DETERMINING YOUR AIRFLOW REQUIREMENT
ASHRAE method
Ventilation Air requirements
Floor area
Bedrooms
0-1
2-3
4-5
6-7
>7
Ft2
m2
CFM
L/s
CFM
L/s
CFM
L/s
CFM
L/s
CFM
L/s
< 1500
<139
30
14
45
21
60
28
75
35
90
42
1501-3000
139.1-279
45
21
60
28
75
35
90
42
105
50
3001-4500
279.1-418
60
28
75
35
90
45
105
50
120
57
4501-6000
418.1-557
75
35
90
42
105
50
120
57
135
64
6001-7500
557.1-697
90
42
105
50
120
57
135
64
150
71
>7500
>697
105
50
120
57
135
64
150
71
165
78
* ASHRAE 62.2-2010 Table 4.1, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings.
Bathroom:
If the ERV is going to provide the required local exhaust ventilation for each bathroom with each a continuous 20 CFM
(10 L/s), this ventilation rate can be considered as part of the whole-building ventilation rate.
