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 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 - VMS

7

8

9

10

11

13

16






Mitsubishi - VMA   



10

10

13

19

26


26

31


37

Mitsubishi - SEZ



9

9

11

15

18

20




Mitsubishi - PEAD




14


17

21

25


34

42

46

Daikin - FBA 15 15 18 18 29 34 34
Daikin - FDXM 9 9 16 16

Daikin - FXSQ-P


9

9

10

16

16

20


25

32

39

46

Daikin - FXMQ


9

9

10

16

18

20


25

32

39


Daikin - FXNQ


7

7

8

11

14

16






Daikin - FXSQ-A

9

9

9

9.5

15

15

21


23

32

36


Fujitsu - ARXB



7


9.8

14

15






Fujitsu ARXD

9


9

10

10

13

16


22.2




Fujitsu ARXA









21

24

31

33

Fujitsu ARXC











43

58