My friend is an electrical engineer. What he does is he use a meter to calibrate the temperature. He told me every aircond has a most economic temperature, what he does is he put in the meter then plug the aircond switch into the meter, then he slowly adjust the aircond until the desire power consumption. E.g. 250KWH. His panasonic inverter is at around 25'C. 250KWH * 8 hrs = 2 unit of electric per day = 60 unit per month. His approach is more scientific. When he put the aircond to lower C. It is amazing to find out the power consumption has almost doubled and reaching 400 KWH. I also get a similar meter to measure my LCD TV. When it is at the brightest, it consumes 200KWH, when i lower the brightness to 75%, it only consumes 120KWH. I've tested almost all the equipment in the house. The most consume electric device is fridge. The more time you open the door, the more time the motor kick off and cool the fridge. My fridge is 306L net one and consuming about 200-300KWH when the motor kick off. Boiling water another evil, it is taking 1000KWH to my surprise. Cook rice/put in warm also another evil, 500KWH. Fan is the most stupid one. No matter what speed you set, you consume the same power. So turn your fan to max to gain the maximum benefit.