Tempco Custom Heater Manufacturing

Kapton® Heater Wattage Recommendations

Determine Required Wattage

Every process has a unique wattage requirement to heat that particular load up to temperature or to maintain a particular temperature.

If the required heater wattage is not known, estimate the required wattage using the thermodynamic formulas listed in chapter 16, Engineering. A safety factor of 25% additional wattage is recommended to compensate for unknown variables.


To raise the temperature of an aluminum plate 6" × 12" × 0.5" (3.53 lb.) 200°F (from 70° to 270°F) in 0.5 hours:

Watts =

3.53 lbs. × (0.24 btu/lb.°F) × 200°F

3.412 btu/watt hr. × 0.5 hrs.

99 watts

Add safety margin: 99 W + 25% = 124 watts


Determine the Heater Size and Watt Density

A flexible heater should use the maximum space available for mounting and heating the process. Factors that affect heater size include the mounting method and watt density.

Watt Density =

Heater Wattage

Area of Heater

As a general rule, the following can be applied for Kapton® heaters:

  • Low Heat-Up:  2.5 w/in2
  • Average Heat-Up:  5 w/in2
  • High Heat-Up:  7.5 w/in2 and greater

Continuing the aluminum plate example, determine what size the heater should be:

  • Kapton® Heater: 5" × 10" = 50 in2
  • Watt Density = 135 watts ÷ 50 in2 = 2.7 watts/in2

Since the watt density falls between 2.5 and 5 w/in2, the heater selected should work satisfactorily.

Suggested Maximum Watt Density by Heater Type and Mounting Method

  Kapton® – Foil Element
Watt Density w/in2 Acrylic PSA Acrylic PSA with
3 mil Aluminum Foil
5 212 to 189°F 302 to 275°F
  (100 to 87°C) (150 to 135°C)
10 189 to 163°F 275 to 257°F
  (87 to 73°C) (135 to 125°C)
15 163 to 131°F 257 to 230°F
  (73 to 55°C) (125 to 110°C)

Note: Use an appropriate Temperature Controller for the application.
View Tempco Temperature Control Products.


See Also:

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Phone: 630.350.2252 | Toll Free: 888.268.6396
Fax: 630.350.0232 | Email: [email protected]

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