How to Compare Rangehood Extraction Rates: What the Numbers Actually Mean
When buying a rangehood, the extraction rate is the most important performance specification. It is measured in cubic metres per hour (m³/h) and tells you how quickly the rangehood can clear air from your kitchen. But the number on the box only tells part of the story. Here is how to interpret it correctly.
What Is Extraction Rate?
Extraction rate is the volume of air the rangehood motor can move per hour. A rangehood rated at 600 m³/h can — theoretically — exchange all the air in a 100 m² kitchen (with a 3-metre ceiling) six times per hour.
The key word is “theoretically”. Real-world extraction performance depends on:
- Whether the rangehood is ducted externally or recirculating
- The length and bends in the duct run
- The size of the duct diameter
- Grease and filter condition
- The fan speed being used
Recommended Extraction Rate by Kitchen Type
| Kitchen Type | Recommended Rate |
|---|---|
| Small apartment / galley kitchen | 400–600 m³/h |
| Standard family kitchen | 600–900 m³/h |
| Open-plan kitchen / island cooktop | 900–1,200+ m³/h |
| High-output gas or wok cooking | 1,000–1,500+ m³/h |
Ducted vs Recirculating — Why It Matters
Ducted rangehoods extract air to the outside through a duct. The extraction rate on the label reflects actual air removed from the kitchen. This is by far the more effective method.
Recirculating rangehoods pass air through carbon/charcoal filters and return it to the kitchen. No air is actually removed — only some odours and particles are captured. For equivalent performance to a ducted unit of 600 m³/h, a recirculating unit needs to be rated 900–1,200 m³/h. Carbon filters also need replacement every 6 to 12 months.
Duct Diameter Matters
The extraction rate on the label is measured under ideal conditions — often with a wide duct diameter. If your installation uses a 100 mm duct but the rangehood is designed for 150 mm, actual performance drops significantly. Use the largest duct diameter the installation allows, and minimise bends.
Noise Level
Noise is measured in dB(A). Below 50 dB is comfortable for everyday cooking. Above 65 dB is loud enough to interfere with conversation. High extraction rates and low noise do not always go together — premium brands (Smeg, Bosch, AEG, Siemens) achieve better noise levels at equivalent airflow.
Matching Rangehood Size to Your Cooktop
- The rangehood should be at least as wide as the cooktop, ideally 100–150 mm wider on each side
- Island cooktops need larger overhead canopy hoods to capture rising steam effectively
- Wall-mounted rangehoods are more efficient than overhead canopy hoods at the same extraction rate
Shop Rangehoods at Oceania Appliances
We carry a range of ducted and recirculating rangehoods from leading brands. Free delivery across Sydney. Visit our Wetherill Park showroom or order at oceaniaappliances.com.au. Call 0493 300 490 for advice.