Common Ventilation Installation Mistakes (And How to Avoid Them)
A practical guide to the most common ventilation installation mistakes, including ducting, fan sizing, and airflow issues, with clear steps to avoid costly performance problems.
Fantech
Fantech Jetline In-line Duct Mounted AC Exhaust Fan - 150MM (6" Inch)
Air Flow 750 M³/H | Power Consumption 83W | IP44
Fantech
Fantech Jetline Eco In-line Duct Mounted EC Exhaust Fan - 200MM (8" Inch)
Air Flow 1050 M³/H | Power Consumption 125W | IP44
Fantech
Fantech Jetline Eco In-line Duct Mounted EC Exhaust Fan - 100MM (4" Inch)
Air Flow 260 M³/H | Power Consumption 19W | IP44
Fantech
Fantech Jetline In-line Duct Mounted AC Exhaust Fan - 125MM (5" Inch)
Air Flow 420 M³/H | Power Consumption 40W | IP44
Fantech
Fantech Jetline Eco In-line Duct Mounted EC Exhaust Fan - 250MM (10" Inch)
Air Flow 1270 M³/H | Power Consumption 160W | IP44
Phresh Hyperfan
Phresh Hyperfan EC Exhuast Fan v2 w/ Controller - 150MM (6" Inch)
Air Flow 560 M³/H | Power Consumption 42W | IPX2
Blauberg
Blauberg Turbo G Mixed Flow Inline AC Exhaust Fan - 315MM (12" Inch) | with Thermostat
Air Flow 1750 M³/H | Power Consumption 315W | IPX4
Blauberg
Blauberg Turbo G Mixed Flow Inline AC Exhaust Fan - 250MM (10" Inch) | with Thermostat
Air Flow 1360 M³/H | Power Consumption 177W | IPX4
Blauberg
Blauberg Turbo G Mixed Flow Inline AC Exhaust Fan - 150MM (6" Inch) | with Thermostat
Air Flow 460 M³/H | Power Consumption 50W | IPX4
Blauberg
Blauberg Turbo G Mixed Flow Inline AC Exhaust Fan - 200MM (8" Inch) | with Thermostat
Air Flow 1080 M³/H | Power Consumption 76W | IPX4
Measure your room (Length × Width × Height) to get the volume, then multiply by the air changes per hour (ACH) you need: Airflow (m³/h) = Room volume × ACH. Bathrooms usually need 10–20 ACH, laundries and kitchens 15–30 ACH, and grow tents even higher.
Air exchange (air changes per hour) is how many times the full room volume is replaced each hour. It’s critical for removing steam, smells and humidity, and for preventing mould and condensation.
AC fans use a traditional AC motor, are cheaper and simple to run. EC fans use a high-efficiency brushless EC motor with electronics, are quieter, more efficient, and allow much finer speed control.
Use only controllers made for AC motors, such as step/transformer controllers, specific AC speed controllers, or the built-in 2-speed function (if provided). The wrong controller can cause noise, poor performance or motor damage.
EC fans are best paired with 0–10V, PWM or dedicated EC/smart controllers. These give smooth, stepless speed control and often allow temperature, humidity or timer-based automation.
Choose AC if you want a budget-friendly fan with simple on/off or 2-speed control. Choose EC if you want top efficiency, quiet operation and precise or smart control, especially for 24/7 or climate-critical applications.
Yes. Long duct runs, tight bends, small duct sizes and filters all reduce airflow. Match the duct size to the fan, keep runs as short and straight as possible, and minimise sharp bends.
Yes, a correctly sized inline fan can exhaust from two or more rooms using junctions (Y/T pieces). Ensure the total room volume and required ACH match the fan capacity, and use dampers to balance airflow.
Most inline fans sit in the roof space or ceiling void, connected to an intake grille inside and ducted to an external vent. The air should always be discharged outside, not into the roof cavity.
Look for insulated or mixed-flow models, check the dBA noise rating, and consider an EC fan so you can run it at lower speeds. Using flexible connectors and anti-vibration mounts also helps reduce noise.