Tempco Sizing a Duct Heater

To properly match a duct heater to an application, the wattage, air velocity and element watt density must be determined.

Formulas and graphs that will aid in your design include:

  • Wattage calculation formulas and table
  • Element Watt Density vs. Sheath Temperature and Air Velocity Graph
  • Pressure Drop vs. Air Velocity Graph

In most applications the following design limitations should be adhered to:

  • Maximum watt density of 40 watts/in2  (6.2 watts/cm2 )
  • Maximum element sheath temperature of 1400°F (760°C)
  • Minimum air velocity of 200 feet per minute (61 meters per minute)
  • Maximum voltage for UL certified heaters is 480V.
  • Maximum voltage for CSA certified heaters is 600V.

Eagle Sensors & Controls is an authorized Tempco distributor. Contact us for sales and application support.