For a thorough check, a special device is used – a winged anemometer that measures the speed of air movement in the ventilation channel. But this is just the beginning. Ventilation performance is measured in m3/h, and in order to get the right information, you need to have a calculated table, and know the section of the ventilation grill. This also needs to be fulfilled by a number of conditions, the neglect of which will significantly change the accuracy of information.