Appliances & Utilities calculator
What Extractor Fan Size Do I Need?
Use kitchen volume, target air changes/hour, duct/filter loss factor to find extractor fan airflow.
Enter your measurements
What Extractor Fan Size Do I Need uses kitchen volume, target air changes/hour, duct/filter loss factor and the other configured measurements to return extractor fan airflow with a formula written specifically for this tool.
- Kitchen volume — Required
- Target air changes/hour — Required
- Duct/filter loss factor — Required
Extractor fan airflow
Enter the measurements above to calculate extractor fan airflow.
How the calculation works
V17 calculation: requiredFlow=kitchenVolume×airChangesPerHour×ductLossFactor/3600. The result is reported as Extractor fan airflow.
Worked example
Example: Kitchen volume = 30000 L; Target air changes/hour = 6; Duct/filter loss factor = 1.2. Result: Required Flow = 60 L/s.
Before you decide
Recheck the limiting measurement before purchase or installation. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what extractor fan size do i need, the limiting result on this page is extractor fan airflow.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Extractor Fan Size calculator tell me?
It returns extractor fan airflow from the measurements entered on this page. The calculation is specific to extractor fan size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for extractor fan size?
Measure kitchen volume, target air changes/hour, duct/filter loss factor. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the extractor fan airflow?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned extractor fan airflow while allowing for the clearances, tolerances or ratings shown by its manufacturer.