Duct Calculator Elite™ is an industry leading tool designed to simplify the job of duct sizing for HVAC professionals. This app allows users to calculate duct size, velocity, pressure drop, and flow rate for ductwork. Duct Calculator Elite™ features a highly intuitive interface which allows users to easily enter values with precision (without the use of cumbersome "slider" controls). In "Duct Size by Airflow" mode, the calculator allows users set airflow and either velocity or friction (Pressure Loss) and the calculator solves for round and rectangular duct dimensions. Aspect ratio of the rectangular duct can also be specified. In "Duct Size by Dimension" mode, users can enter either a round duct diameter or rectangular duct height and width. In addition, users can lock airflow, velocity, or friction and solve for the other variables. In "Pressure Drop" mode, users can convert between duct length, pressure drop, and friction values. This allows users to quickly determine exact pressure drop of a given installation or calculate the max duct length that can be used to maintain desired pressure drop. This feature compliments the two duct sizing calculators. Duct Calculator Elite™ provides users with a wide variety of preference setting including: -Duct Dimensional Units (Inches, Centimeters, or Millimeters) -Airflow Units (Cubic Feet per Minute, Cubic Feet per Second, Cubic Meters per Second, or Liters per Second) -Velocity Units (Feet per Second, Feet per Minute, or Meters per Second) -Pressure Loss Units (Inches of Water per 100ft or Pascals per Meter) -Duct Material (Aluminum, Concrete, Fibrous Glass Duct Liner, Flexible Duct-Metallic, Galvanized Steel, PVC Plastic Pipe, Smooth Liner, Spiral Steel, or Uncoated Carbon Steel) -Air Temperature (Fahrenheit, Celsius, or Kelvin) -Elevation (Feet or Meters) The Duct Calculator Elite™ solver uses friction loss equations contained in 2009 ASHRAE Handbook - Fundamentals. The next time you go to a meeting or out to the field, leave your Ductulator at home, you'll have everything you need right on your iPhone/iPad/iPod Touch! If you are not 100% satisfied with this calculator please email us at [email protected] so we can make things right before posting any negative reviews. We read all emails. We are also open to any suggestions you may have for future enhancements to this app.