Developer's DescriptionBy Smart Apps GeniusHVAC Duct Calculator developed by Smart Apps Genius group is a handy App for air duct sizing and pressure drop calculations, useful for both...HVAC Duct Calculator developed by Smart Apps Genius group is a handy App for air duct sizing and pressure drop calculations, useful for both round and rectangular ducts. A unique feature of this App is that it enables the user to select the unit of parameters in any combination. Calculation of pressure drop has been based on Darcy-Weisbach equation and Colebrook formula.