Take the power consumption (P) in Watts of the target multiply with 3.41214 (coefficient).  The result is in BTU/hr.

Heat Dissipation (BTU/hr) = P * 3.41214

Depending on the electronic components used and the environment the Magelis terminals are in will determine the heat dissipation.  But Engineering likes to give the heat dissipation as 100% dissipation due to many factors that determines the heat dissipation.

A portion of the power entering an iPC target gets transformed into light, by the backlight that allows the user to see the user application on the screen. Another portion of that power is transformed into heat. Unfortunately, it is impossible to determine how much heat is created and therefore how much power is dissipated. This depends on the conditions in the environment.