Duct Designer

The duct designer lets you plan ductwork runs for ducted AC systems — complete with sizing calculations, airflow distribution, and a visual schematic.

Where to find it

Open a quote with a ducted system and tap Duct Design. The designer is linked to the quote's ducted unit.

How it works

System parameters

Start by setting the overall system specs:

• Total airflow (L/s) — from the ducted unit's rated capacity
• External static pressure (Pa) — the unit's available pressure
• Max velocity (m/s) — design target for duct sizing
• Duct roughness — material roughness factor

Build the duct tree

The layout is modelled as a tree:

1. Trunk — the main supply duct coming off the unit
2. Branches — secondary ducts splitting off the trunk
3. Flex runs — final flex duct connections to each room grille

For each element, set the length, size, and fittings. The designer calculates pressure drop and velocity automatically.

Return air

Configure the return air path separately — return grilles, filter box, and return duct back to the unit.

Rooms

Each flex run connects to a room. Enter the room's cooling requirement (kW) and the designer distributes airflow proportionally and checks that each room gets enough.

Schematic view

Switch to Schematic to see a visual diagram of your duct layout — trunk, branches, and flex runs drawn to proportion. Tap any element to select it and see its properties in the sidebar.

Results table

The Results view shows a summary table:

• Each room with its required vs. delivered airflow
• Duct sizes and velocities throughout the system
• Total pressure drop vs. available static pressure
• Warnings if any section is undersized or over-velocity

Tips

• Start with the unit's rated airflow and static pressure from the equipment catalog
• Keep flex runs under 6m where possible — longer runs lose more pressure
• Check the results table for velocity warnings — noisy ducts are a common complaint
• Save the design — it stays linked to the quote and appears in the PDF