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duckTED by It's Engineered - download links and tutorial

Download and install duckTED for your phone (from Google Play here first) & read on…

Maybe even watch a quick tutorial on YouTube (here)

Using the duckTED app:  

Thanks for using duckTED

You're cruising at 21,001 feet with beta version 0.9


As you’re about to discover, duckTED is like no other duct design software currently available. duckTED is fast and easy to use. duckTED's display is compact and easy to understand. duckTED has been developed with the design engineer in mind. Many “what if…” questions are answered alongside the sought solution, with many more “what if…”’s only a few steps away.

When using duckTED, keep the following key points in mind:

1.      duckTED is an engineering tool and must be used with understanding and respect. If duckTED is used with such care, answers will be reliable and trustworthy.

2.      Plan your work and be prepared before you start. If ducks could design effective ductwork systems on their own, they wouldn’t be flying to warmer climates during the cold season!


Well, the easiest way to begin understanding duckTED is to dive right in.

NOTE: This tutorial is written based on metric applications. If you'll be working in imperial, you'll find that option in the menu.

When duckTED starts, the cursor position will default to the Airflow field. Here, you enter the volume of air flowing through the duct section in Litres per second. For example, the 1600 L/s required to adequately ventilate the office wing. So, type “1600” and press Enter.

The cursor position has now moved to the Flow field. Here, you enter the desired height of the required duct section in millimetres. For example, you have determined that a duct with a 350mm tall section is to be installed in the available ceiling space. So, type “350” and press the Enter key.

Done. After just two entries, Ted presents you with your required duct size.


Your duct selection is presented to you as a range of 5 immediate options. These 5 options range from short wide sections at the top of the list to tall narrow sections at the bottom, with your originally desired section height in the middle, indicated by the BOLD text through the middle row of the list.

For each of the selection options, Ted presents a Width, a Height, a round duct size (for equivalent friction, then rounded up), a Flow Velocity and the Pressure Loss per metre of straight duct.

All selection sizes are rounded up to the nearest 50mm by default. This can however be changed to suit your preferences (see Options in the menu). The 5 options displayed, will be separated by 50mm in height, as alternatives to your original suggestion.

Five options not enough?  Press the FLATTER and TALLER buttons and you can browse through more selection options.

But why is the pressure loss and velocity of your selection under 0.8 Pa/m or 6 m/s? Let's look into that...


By default, duckTED will size ductwork based on limits of 0.8 Pa/m and 6 m/s. Ted optimises the selections and decides the smallest duct cross section that will not exceed these limits at the entered flow rate. (The limits are rarely achieved due to the 50mm size rounding increments.)

To change the selection limit from 0.8 Pa/m and/or 6 m/s to some other value, alter values in the Limits section at the bottom of the screen. Change the defaults for these values via Options in the menu.

Why are some of the duct dimensions orange or red?

Soundly engineered duct design includes consideration of width:height ratios.

If this ratio exceeds 4:1, the dimensions will be orange

If it exceeds 6:1, these will be red

4 calculation basis options are included below the selection window:

• Cap Pa/m,

• Cap m/s,

• Cap Both and

• Analyse

The next required section of duct has the same height and flow rate as before, but due to noise limitations, a velocity no greater than 3.5 m/s must be used as the selection basis. To ask Ted for some more options based on this new criteria, select the Cap m/s option button for the calculation basis, type “3.5” in the corresponding Limits field and press Enter. 5 new selections, each with a velocity no greater than 3.5 m/s will now appear.

Use the Cap Pa/m option to ignore velocity and size your duct based on pressure drop alone.

Use the Analyse calculation option to ask Ted about the conditions in a duct of known cross section and a flow or velocity. Select the Analyse option and type the height and width in the fields at the top and the known condition in m/s or L/s field. This time, Ted will only offer one set of information – indicating the flow conditions and equivalent round duct section for the analysed duct.


duckTED’s biggest downfall is that Ted cannot think for himself.

duckTED is an engineering tool designed to be used by suitably experienced engineering professionals who posses sufficient knowledge and experience to identify anomalies and are willing to apply engineering common sense.

duckTED was developed for quick estimates only. More detailed calculations are required as part of the design process.

If for some reason, a solution suggested by Ted appears unreasonable, investigate why it’s unreasonable.

This requires suitable knowledge and experience in duct design.

The sizes of ductwork sections suggested by Ted are usually no less than three times the duct size round off value (50mm by default) in one dimension. This is due to the iterative procedures used in the calculations and should not pose any difficulties for typical duct applications.

duckTED's maximum dimensional values can be huge. These maximums are limited by the size of duckTED’s display and calculation methods, however, at any unusual dimensions the accuracy of the empirically derived equations never been accurately tested and these are not recommended.

When used correctly, duckTED will accurately predict flow characteristics, with appropriate sectional sizes for typical ductwork applications.

For more complicated applications, it is recommended that you use more sophisticated (and subsequently more expensive) flow modelling software.

As with any software package, or engineering application, you must become familiar with duckTED before using it in design situations.


I recommend self-testing duckTED's results against trusted charts, dog-earred Ductulators (thanks Trane for many years of my Ductulator's service!), spreadsheets etc, before confidence can be established.

Be an engineer about it.

and Enjoy!

Living in the past? Looking for the original PC-based version of duckTED? (download it for FREE here)