Which AC Tonnage Do I Need? 1 Ton vs 1.5 Ton vs 2 Ton

Room size is the starting point

Measure the floor length and width in feet and multiply them. A 10 × 12 ft bedroom is 120 sq ft; a 12 × 15 ft living room is 180 sq ft. Cooling need grows with the area, so this number gets you to the right tonnage band.

When to go one size up

Heat that enters the room matters as much as its size. The same 150 sq ft room can need a 1.5 ton AC on a shaded lower floor and a 2 ton AC under a sun-baked roof.

• Top floor or directly under a roof or terrace
• West-facing walls or large windows that get afternoon sun
• Ceilings higher than about 10 ft
• Three or more people in the room for long hours
• A kitchen or other heat source opening into the room

What goes wrong with the wrong size

An undersized AC runs flat out and still leaves the room warm on the hottest afternoons, and its compressor works harder than it should. An oversized AC cools the air quickly but switches off before it removes humidity, so the room feels cold and damp, and you pay more up front for no benefit.

Inverter ACs soften both problems because they adjust their speed, but the right size still matters most.