You can calculate the heat dissipation based on the efficiency of the specification:
output power / efficiency = input power
input power – output power = internal power loss
Then, you can convert the loss to calorie.
Let’s take PWR401L as an example.
The specification of its efficiency is 75%:
400 W/0.75 = 533 W
533 W – 400 W = 133 W
133 W x 0.86 kcal/h = 114.38 kcal/h
Therefore, the heat dissipation will be 114.38 kcal/h.
For the efficiency, read the user’s manual – chapter of Specifications.