Hands holding a steel tape measure along a bedroom floor in a flat with a grilled window — AI-generated picture. Two measurements and a look at the sun. It takes five minutes and can save years of a wrongly sized unit.

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Measuring the room before you buy

For which ton AC suits which room size, LG India's guide gives up to 120 sq ft for 1 ton, 120–180 sq ft for 1.5 ton and 180–240 sq ft for 2 ton, and sun, a top floor or a crowd can push a room up a size.

From The AC in Your Flat. Updated 4 November 2026.

A ton in AC talk has nothing to do with weight. It's a rate of removing heat. The Press Information Bureau equates 10,465 watts of cooling with 2.97 tons, so one ton is about 3.5 kW. (LG's page prints "3500 kW" where it means 3,500 watts.)

Room size and capacity, LG India's guide of May 2026
Room size	Capacity	Typical room
Up to 120 sq ft	1 ton	Small bedroom, study
120 to 180 sq ft	1.5 ton	Main bedroom, mid-size room
180 to 240 sq ft	2 ton	Large bedroom, living room
240 sq ft and above	More than 2 ton	Hall, open-plan living area

Which ton AC for a room size in my city?

Start with LG's table, then adjust. LG suggests going a size up for dry extreme heat in Delhi, UP and Rajasthan, and treats Pune, Bengaluru and Hyderabad as standard. For Mumbai, Kolkata and Chennai it puts dehumidification first. This is one maker's guide. Other makers' charts differ, sometimes by a good deal, so look at a couple. A technician can do a proper load estimate if the room is odd.

Olive and cream apartment blocks beside a wide road under a bright sky — Sun on the road side of a block means the rooms that face it often need more than the table says.

What pushes a room up a size?

Heat from outside and heat from inside. Top-floor rooms under a terrace, west-facing glass, a kitchen next door and many people in the room all add heat. LG says more cooling than you need means higher bills and uneven cooling, so don't overbuy to be safe.

A narrow lane between old pale blocks in a Pune housing society with scooters parked along one side — Blocks this close shade each other. A first-floor room here may need less than the top floor of the same building.

Can you fit a bigger AC on the same wiring?

Don't assume it. The larger unit may need different wiring and protection. An electrician decides that. Check it with the MCB and wiring story and your sanctioned load, as the Central Electricity Authority's 2026 advisory asks.

What to do

Yours to do

Measure length and width, and multiply for square feet.
Note top floor, sun, kitchen and how many people use the room.
Check capacity in the spec sheet, not just the word on the box.

Leave to the trained person

A load estimate for an unusual room, and the wiring check.

Also asked

What about a very high ceiling?

Square-foot tables assume a normal ceiling. Tell the technician the height, and ask for a load estimate.

Is a slightly bigger AC harmless?

LG says it brings higher bills and uneven cooling. The opposite error leaves the room never truly cool. Aim for the table, then adjust for the real causes above.

Where this came from

LG India, AC capacity guide, May 2026: Table and climate notes
Press Information Bureau, 6 January 2020: Watts per ton
SolarQuarter, 10 July 2026, on the Central Electricity Authority advisory: Sanctioned load, as reported

This story rests on those pages, opened or checked by 4 November 2026, and on no tests of our own. Maker pages speak for their makers, and rules and wiring differ by building, so check your own manual.