India, May 12 -- As temperatures across India breach the 45degC mark, the scramble for the perfect Air Conditioner has reached a fever pitch. But walk into any appliance store, and you'll likely hear the same generic advice: "1.5 Ton is enough for a 150 sq. ft room."

For thousands of Indian homeowners, especially those living on the top floor or in modern apartments with high ceilings, this "standard" advice is a magnet for a warm room and a massive electricity bill.

If your AC is running for hours but the "chill" never arrives, you aren't just facing a heatwave; you're likely a victim of a tonnage calculation error. Here is the definitive guide to calculating AC capacity for the "non-standard" Indian home.

In a middle-floor apartment,...