This Air Current Test Kit is a quick and inexpensive way to help make these determinations. It works by creating a highly visible non-irritating dense white smoke that can be followed to determine the airflow direction.
Zefon Price: $117.00
The TSI VELOCICALC® Model 9565-P is a portable, hand-held, multi-function ventilation test instrument featuring a menu-driven user interface for easy operation in your local language.
Zefon Price: $1415.00