HVAC (Heating, ventilation, and air conditioning)

Who better to need or understand wind currents and thermals than the HVAC techs and installation companies. HVAC professionals have discovered Windindicators and they are replacing the traditional smoke pens and large bulky smoke machines used for decades. 

"The durable and long lasting Cirrus™ Wind Indicator delivers what seems like a never ending supply of battery and vapor to detect currents in closed systems, vents, positive and negative rooms  not to mention we use it for ventilation of refrigeration systems." -   B. MacDowell