200mm to 150mm Ducting Reducer Collar — 8" to 6"
This reducer collar steps down the ducting diameter from 200mm (8") to 150mm (6"), connecting a 200mm round motor housing spigot to a 150mm round ducting run. It is most commonly used where a high-powered cooker hood with a 200mm motor outlet needs to connect to an existing 150mm duct run.
Important — Performance Warning Before Reducing
Cooker hoods with motor ratings between 950m³/hr and 1,350m³/hr must be installed with 200mm (8") ducting to maintain full extraction performance and quiet operation. Reducing to 150mm is possible using this collar but will increase operational noise levels — the restriction forces the motor to work harder to push the same volume of air through a smaller duct opening, which is audible as increased fan noise throughout the duct run. If 200mm ducting can be installed, it should always be the preferred choice for these motor ratings.
Use this reducer only where 200mm ducting is genuinely not achievable for the installation — for example, where an existing 150mm duct run is already in place and cannot be replaced, or where physical constraints in the building prevent 200mm ducting from being routed.
Where This Component Is Used
This collar connects the 200mm round spigot of the motor housing directly to the start of a 150mm round duct run. Always check your motor outlet diameter and intended duct size before ordering to confirm this is the correct reducer direction for your installation.
Ducting Size Guide
Selecting the correct ducting diameter for your motor output ensures maximum extraction performance:
- Below 450m³/hr → 100mm (4") ducting
- 450–750m³/hr → 125mm (5") or 150mm (6") ducting
- 750–2,000m³/hr → 150mm (6") or 200mm (8") ducting
