Kitchen rangehoods are great at removing heat, moisture, organic pollution (grease), and cooking odours—when they’re ducted correctly. However too often, poorly ducted rangehoods deposit grease that builds up over time to create an unhygienic kitchen.
Classic Cooktop and Oven Paired with Island Rangehood SHI410X1 by Smeg
Common issues we see.
The duct size is too small
The duct run is too long, or has too many bends
The duct opens into wall cavities or the ceiling, rather than to outside
The flexi duct has collapsed or is occluded
There’s insufficient provision for return air, creating negative room pressure (a common cause of odour seepage from adjoining rooms)
No ducting at all!
Fixing rangehood ducting problems is challenging and often very expensive, mainly because issues only come to light weeks or months after installation. And, when you need access into roofs, wall, or ceiling cavities to fix a ducting problem, clean-up costs can be hefty indeed.
Far better to get it right the first time.
How to ensure good extraction – 6 things to know.
Rigid & Semi-Rigid Ducting | Image: Sirius Australia
1. Know your duct. Ducting types fall into four main categories each with different requirements: flexible, semi-rigid, rigid, and recirculating. Unsure what these are? Download our Ducting Quick Guide to get up to speed.
2. Size matters. Your duct diameter or aspect ratio must match or exceed the rangehood’s motor outlet to extract air correctly and work quietly.
3. Performance drag. Constricted ducts reduce rangehood effectiveness dramatically. With today’s high-power extractors operating at up to 3000cu/m3 per hour, high-performance hoods can create backpressure, blowing odours back into the kitchen if the duct is constricted.
4. Good rule of thumb. For most conventional onboard motor hoods, a duct run of up to 5 metres or more is on the edge of capability, especially when every 45/90-degree bend equals a 1 metre straight run in air resistance terms. Need a solve for longer duct runs up to 20 metres? Rangehoods with off-board or remote motors are a great option and also reduce noise because they’re located externally. Check out Sirius for some simple, practical solutions to improve performance, lower noise, and boost flexibility for long runs.
Reference Guide to Complete Motor Solutions by Sirius Australia