I have seen most of the time that, when we go to buy Air conditioner, then we ask the salesperson to suggest a good AC for us. He/She does not know anything about our home location, room size or number of people going to stay in that room. So they just suggest the model which will fit all conditions, no matter what.

So most popular model is 1.5 Ton AC. Ask any salesperson about AC and they will start showing you the 1.5 Ton models they have. They will never ask you any questions as mentioned above.

And it has little benefits for them. Because bigger AC will result in more money in sales. What more they even do not keep many 1 Ton ACs in stock. Only 2-3 pieces/models you can find. And for 1.5 Ton AC there will be more than 20-30 options.

Most of us live in a moderate size house. With the average bedroom size of 10 x 12ft. Even if your room size is 12ft X 15ft then also 1 Ton AC will be more than enough for you. But we have a inherent fear that - what if it does not work for my need? Then what am i going to do with it. Do not worry.

Here is size breakup of the AC requirements:

In addition to saving money when you buy an AC, it will save a lot more money in the long run. More details given below:

The 1.5 Ton AC needs around 2KW of power, whereas 1 Ton AC needs only 1.2KW of power. So if you have 2 ACs of 1.5 Ton then total load on your electric meter will be 4KW for AC only, so you will need at least 5 KW power connection.

Where as with two 1 Ton AC the load will be 2.4KW, hence only 3KW connection will do.

We all pay a fixed rent based on load. So higher the load more then rent.
In UP it is Rs.90 per month so every month you will be paying Rs. 180.00 as fixed cost.

Now let us compare the difference during usage.
Two 1.5Ton AC Usage for 12 hours - Total Power usage - 48 Units
Two 1 Ton AC Usage for 12 hours - Total Power Usage - 29 Units

At Rs. 6 per unit the difference will be - 48 * 6 - 29*6 = Rs.114 per day.

So in a year suppose if you use AC for even 6 months then the total saved money will be - 
Rs. 180 * 6 = Rs. 1,080.00
Rs. 114 * 6 * 30 = Rs. 20,520.00

Total: Rs.21,600.00. Which is more than the cost of 1 Ton window AC.

And this is for 1 year only. If you use it for 5 years then the total savings will be Rs. 108,000.00, just in electric bills.

And the cooling and other benefits will remain same. Many a time we do not use AC to save amount in Bills. So if you use the 1 Ton AC you can enjoy the cooling for more time of day and have to pay less also.