A manufacturer like Carrier or Panasonic listed their 1 Horsepower Aircon as having 9,500 KJ/h and 1.5 Horsepower Aircon as 13,000 KJ/h. But it doesn't tally with the BTU conversion. 1 ton refrigeration = 12000 Btu/Hour = 12,661 kJ/Hour = 3.517 kW now 1 watt = 0.00134102209 horsepower therefore 3.517 kW = 4.7 Horsepower! But the Carrier/Panasonic manufacturer listed 1.5 Horsepower Aircon has having 13,000 KJ/hour which is equivalent to 12000 Btu/Hour or 1 ton. Yet calculation of this data show 4.7 Horsepower. Why did Carrier/Panasonic, etc. listed them as 1.5 Horsepower Aircon? I've been searching in net for this for hours but can't find the reason. Anyone got any idea why?