Daily · Free tool
AC Tonnage Calculator
Right-sizing matters: undersized AC runs all day and never cools; oversized AC short-cycles and wastes energy. Rule of thumb: 1 ton per 130 sqft, adjusted for climate and floor.
150 sqft
10 ft
2
Recommended AC
1.5 ton
Calculated need: 1.33 tons (15923 BTU/hr)
Inverter or non-inverter both fine; inverter still saves 15-20%.
FAQ
What ISEER rating is right?
5-star: 4.5+ ISEER, ~₹600-900 / month for 1.5T at 8 hrs/day in Delhi summer. 3-star: 3.5-4.0 ISEER, 30% higher running cost.
Window AC or split?
Split — quieter, more efficient (modern inverters), better aesthetics. Window is cheaper upfront and easier to install but rarely sold above 1.5 ton. For long-term, split is the standard.
Is buying an AC worth it for < 4 months of summer?
Up to 6 weeks: probably not. 6 weeks - 3 months: marginal — air cooler often suffices. 3+ months: yes, especially Delhi/Rajasthan/Hyderabad.