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
1
2
3
4
5
Ft2
m2
CFM
L/s
CFM
L/s
CFM
L/s
CFM
L/s
CFM
L/s
<500
<47
30
128
38
18
45
21
53
25
60
28
501-1000
47-93
45
21
53
24
60
28
68
31
75
35
1001-1500
94-139
60
28
68
31
75
35
83
38
90
42
1501-2000
140-186
75
35
83
38
90
42
98
45
105
49
2001-2500
187-232
90
42
98
45
105
49
113
52
120
56
2501-3000
233-279
105
49
113
52
120
56
128
59
135
63
3001-3500
280-325
120
56
128
59
135
63
143
66
150
70
3501-4000
326-372
135
63
143
66
150
70
158
73
165
77
4001-4500
373-418
150
70
158
73
165
77
173
80
180
84
4501-5000
419-465
165
77
173
80
180
84
188
87
195
91
* ASHRAE 62.2-2016 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.
