A normal one ton AC uses on an average about 1.25 units of electricity every running hour. This of course will vary depending on many factors like outside temperature, insulation factor of the room, etc., but 1.25 units of electricity is about the average. The 1 ton inverter AC power consumption per hour would be about 40% less than that of a one ton normal AC. That means the power consumption of a 1 ton inverter AC will be about 0.75 units of electricity. Assuming 8 hours of operation per day, that will be 10 units of electricity per day for normal AC and only 6 units per day for a 1 ton inverter AC.
Thus the monthly power bill for a normal AC, assuming Electricity cost at Rs.5- per unit, will Rs.1,500- per month compared to Rs.900- for a 1 ton inverter AC. Therefore the saving in electricity cost of a 1 ton inverter AC for a month is Rs.600-, and Rs.7200- per year.
In the above example let us say that the 1 ton inverter AC costs Rs.10,000- more than the normal 1 ton AC, then with the monthly electric bill saving of Rs.600 per month, you will have paid off this extra money for the inverter AC in a matter of about one and half years. If you use the inverter AC for 5 years, then you will have saved more money with the inverter AC than the cost of the AC itself.
Apart from the cost savings in the running costs of an inverter AC, you will have a much more silent AC. The room temperature with an inverter AC will be always comfortable without the room becoming too cold for some time and then becoming too warm like with a normal AC.