SCADAPack 334E power consumption in the worst case is about 4.9W (4.5 + 0.3 + 0.020*24*2) with Analog outputs drawing full current.
Approximately 100% of the RTU's power consumption is converted into heat energy (a small amount will be converted into light energy rather than heat energy due to LEDs).
So the RTU outputs a little under 5 W of heat energy. This doesn't include the heat output of other devices or the external power supply that is providing power to the RTU.