The rated wattage is just RMS wattage, and thats only important for what you pay at the meter. The REAL power, ir instant power, is what the RMS power is divided by to get the power factor. On a kill-a-watt, its VA. PF is used to calculate pump efficiency. So I can have a pump with a RMS wattage of 40, but if the power factor is .3 (some cheap knock-offs like the AquaEuros and Gen-X are in this realm), that means that the pump is really using 133 watts, and at least 93 watts of that is going straight to heat!
So thats why I ask for the VA as well as RMS. As far as heat that you may or may not feel... its relative, even with external. The only way to know for sure is to track the electricity... besides... aren't these pumps external/water cooled?