Air changes per hour
Calculate estimated ACH from room size and extract or supply airflow.
Useful tools
Ventilation calculators.
Quick estimating tools for air changes, airflow, duct area, air velocity, air volume and airflow conversions.
These calculators are intended as quick guide tools only and should not replace a project-specific ventilation design. Final ventilation design should take account of system resistance, fan performance, noise, regulations, access, maintenance and site-specific requirements.
Airflow required for target ACH
Estimate the airflow needed for a given room size and air change rate.
Circular duct area
Calculate duct area from circular duct diameter.
Rectangular duct area
Calculate duct area from rectangular duct width and height.
Air velocity
Estimate air velocity from airflow and duct size.
Air volume / airflow
Estimate airflow from air velocity and duct size.
Airflow conversion
Convert between m³/h, litres per second and m³/s.
Important design note
These tools provide indicative figures only. Air volumes, duct sizes and fan selections should be checked against the actual application, pressure losses, noise limits, filtration, heater/cooling coils, access requirements and relevant guidance or regulations.
Start an enquiry
Need a ductwork or ventilation quotation?
Send your enquiry direct to Airduct and include any drawings, photos, sketches, room dimensions or equipment details that may be relevant. We can review the information and advise whether a site survey is required.