Kitchen ducting information

Useful kitchen ducting information and tips.


Kitchen ducting tips.

Round ducting provides the most optimum performance for airflow. Rigid round ducting is far more effective than flexible or rectangular flat channel ducting.

If you do use flexible ducting ensure that it is taut and is as straight as possible. Keep bends to a minimum use 2 x 45º bends rather than a 90º bend, which will help airflow.

Choose the shortest and most direct route to an outside wall.

If you reduce the size of your cooker hood ducting the ducting may be noisy and you could invalidate your cooker hood warranty.


Kitchen ducting sizes explained.

What size kitchen ducting do I need?

When installing a cooker hood you will require some kitchen ducting for your extractor. The cooker hood instructions will suggest the size of ducting that is required which is normally quoted in round ducting sizes, these are 100mm, 120mm, 125mm and 150mm.

The 120mm size let me explain, the spigot on the hood may be 120mm but the nearest to that size in round ducting is a 125mm internal diameter. We sell a wonderful part called a round spigot adaptor our model no. D5/RSA this fits over the 125mm rigid round pipe. The rubber gasket then pushes over the cooker hood spigot to provide a tight seal.

When installing round ducting obstacles can get in the way, joists and other building items. So rectangular flat channel ducting is an alternative especially with restricted spaces in ceiling voids.

By running rectangular flat channel ducting across the top of kitchen units, the kitchen ducting can be concealed due to the low profile and be more aesthetically pleasing.


Listed below are the rectangular flat channel ducting alternatives to round ducting for cooker hood ducting.


Round ducting Free Area Rectangular ducting Free Area
100mm round kitchen ducting 7855mm 110mm x 54mm 5424mm
125mm round kitchen ducting 12273mm 204mm x 60mm 11452mm


150mm round kitchen ducting 17673mm  220mm x 90mm          18545mm 


The Naples Team