Please look into the rated power input at 100% load on your AC box. For example, if the rated input for a 1.5-ton AC is 1500 W/Hr, we can calculate how many units of electricity the AC may consume if you run the AC for 8 hours a day with 100% load. Total Power consumed per day =1500X8= 12000 W/Hr= 12000/1000 KWhr=1.2 KWhr= 1.2 Unit.