Selecting the right integrated cooker hood is a balance of fluid dynamics, cabinet dimensions, and thermal management to ensure efficient moisture and grease extraction. To achieve optimal performance, you must align the appliance's extraction capacity with your kitchen's volume and the specific thermodynamics of your cooktop.
Calculating the Required Airflow Capacity
The primary metric for cooker hood efficiency is its extraction rate, measured in cubic metres per hour (m³/h). As a scientific rule of thumb, a kitchen's air volume should be filtered or replaced approximately 10 to 12 times per hour. To calculate your ideal capacity, multiply the room's length, width, and height to find the total volume in cubic metres, then multiply that figure by 10 and 12 to find the minimum and maximum capacity range.
For example, a kitchen measuring 4m by 3m with a ceiling height of 2.5m has a volume of 30 cubic metres. This space requires a hood with an extraction rate between 300 m³/h and 360 m³/h. If you cook with high-heat techniques like stir-frying or searing, which generate dense particulate matter and rapid thermal plumes, aim for the higher end of this calculation or select a hood with an intensive boost mode.
Matching Hood Width to the Rising Thermal Plume
When cooking, steam, grease, and odour do not rise in a straight vertical column; they expand outwards in a cone-shaped thermal plume. The angle of this expansion is typically between 10 and 15 degrees. For effective capture, the hood's extraction surface must cover or exceed the width of the cooktop beneath it.
- Standard 60 cm Hobs: Require an integrated hood of at least 60 cm width. If your cabinetry allows, a 70 cm or 80 cm hood mounted inside a wider cabinet will capture stray steam more effectively.
- Canopy vs. Telescopic Hoods: Canopy hoods remain completely flush inside the cabinet base, relying purely on static suction. Telescopic (slide-out) hoods pull out physically to extend the capture zone over the front rings of your hob, making them highly efficient for deeper cookware.
Extraction versus Recirculation: The Filtration Science
Your choice between ducted extraction and recirculation dictates how the hood processes air. Extraction systems channel air outside via ducting. For optimal fluid dynamics, use smooth-walled rigid ducting rather than flexible corrugated hose, as ridges create turbulence, reducing airflow efficiency and increasing noise levels.
Recirculation systems rely on internal filtration. The air first passes through a metallic grease filter, where airborne grease droplets condense onto the cooler metal mesh through physical impaction. The air is then forced through an activated carbon filter. Activated carbon operates on the principle of adsorption, trapping volatile organic compounds (VOCs) and odour molecules within its highly porous structure. Because carbon filters restrict airflow, a recirculating hood requires a slightly higher motor capacity than a ducted one to achieve the same effective clearance rate.
Installation Heights and Condensation Management
The installation height of your integrated hood directly affects both safety and extraction efficiency. The ideal distance depends entirely on your energy source because gas and electric/induction cooktops generate different thermodynamic patterns.
With gas hobs, open flames generate significant ambient heat, requiring a minimum clearance of 65 cm to 75 cm to prevent the hood's components and grease residues from overheating. With induction hobs, the cooktop itself does not generate radiant heat; only the cookware heats up. While this allows for a lower installation height (usually 50 cm to 65 cm), it introduces a different physical challenge: rapid condensation. Because the surrounding air remains cool, rising steam cools quickly and condenses into water droplets upon hitting the cold underside of the hood. Selecting a hood with a slight incline or heated glass panels can mitigate this condensation drip.
