Velocity Calculator

Use this handy form to help you calculate the average velocity in each of your ducts when fitting an above ceiling ducted air conditioning unit.

As a guide, duct velocities should be designed around 3 - 3.5 m/s and should not usually exceed 5 m/s. If you achieve a value higher than 5m/s then we recommend that you review your ductwork sizing.

Airflow rates on high fan speed for various AC manufacturer’s indoor ducted units are shown below.

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Airflow (M3/min) of various ducted AC units for different nominal outputs (Kw) when set at high speed


1.5

2.0

2.5

3.2

4

5

6.3

7.1

8

10

12.5

14

Mitsubishi - VMS1-E

7.0

8.0

9.0

10

11

13

16.5






Mitsubishi - VMA-E


8.5

8.5

10.5

14

17

19


21

33

40


Mitsubishi - SEZ-KD



9.0

11


15

18

50





Mitsubishi - PEAD-RP




14


17

21

25


34

42

46

Daikin - FXSQ-P


9

9

9.5

16

16

19.5


25

32

39

46

Daikin - FXMQ


9

9

9.5

16

18

19.5


25

32

39


Daikin - FXNQ


7

7

8

11

14

16






Daikin - FXSQ-A

8.7

9

9

9.5

15

15.2

21


23

32

36


Fujitsu - ARXB



7.3


9.8

14.3

14.8






Fujitsu ARXD

8.5


9.2

10

10

13.3

15.7


22.2




Fujitsu ARXA









21.3

23.5

31

33

Fujitsu ARXC











43

58