@manpreet02 The way I suggest is to buy a Mains Power MeterThe one in the link is from Jaycar, but similar units are available at other retailers and online.These units will show how much power the device is using. You can then work out if it is worthwhile changing to more efficient appliances.The devices which will use most power are those which Heat or Cool. So Refrigeration, Air Con, Hot Water Heaters, Space Heaters etc.