When you plan AC for a shop, salon or restaurant, tonnage is usually where the confusion begins. One vendor recommends 1 ton, another suggests 1.5 tons, and a third tells you to install 2 tons “for safety”. Most owners either guess or pick the middle number.
If the capacity is too low, the AC runs for long stretches, corners of the room stay warm in peak hours and your electricity bills stay high for the comfort you get. If the capacity is too high, the system cools too quickly, keeps switching on and off and still leaves the air feeling uneven.
In a customer facing space, this shows up in full restaurants that feel stuffy at the back, salon chairs that never feel quite cool enough, or gyms where the floor feels heavy even with the AC on full. Getting tonnage roughly right at the start avoids a lot of that.
What AC tonnage actually means
Tonnage is a measure of cooling power.
In air conditioning terms, 1 ton is the capacity to remove roughly 3.5 kW of heat from a room in an hour. Higher tonnage means the AC can move more heat out of the space each hour.
For you, the real question is simple. How much cooling power does each room need in your busiest hours, given its size and use.
Quick sizing guide for common business spaces
Most AC guides in India use room size as a starting point. The ranges below adapt those charts for typical business rooms. These are thumb rules, not final designs.
| Space type | Approx. area (sq. ft.) | Indicative AC size | Notes |
|---|---|---|---|
| Manager cabin or consulting room | Up to 100 | Around 1 ton | Low people count, normal office equipment |
| Salon room, treatment room, clinic box | 120 to 150 | Around 1 to 1.5 tons | A few staff and clients, bright lights, some equipment |
| Small retail shop or cafe | 150 to 250 | Around 1.5 to 2 tons | Steady footfall, display lighting, sometimes small kitchen kit |
| Open office bay or co working zone | 250 to 400 | Around 2 to 3 tons | 6 to 12 people with laptops, often as 2 smaller units |
| Small gym studio or group class room | 300 to 500 | 3 tons and above | Active users, machines, higher internal heat load |
These ranges assume regular Indian conditions and normal ceiling height.
When Can Tonnage Vary?
Two rooms can have the same area and still need different AC capacity. The main reasons are:
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People count
A 200 sq. ft. waiting area with 2 people most of the time needs less capacity than a 200 sq. ft. salon or open office with 6 to 8 people working all day. Gyms and busy salons usually need more tons per square foot than quiet offices.
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Equipment and activity
Ovens, fryers, refrigerators, treadmills, cardio machines, computers and strong lighting all add heat. A small bakery, cloud kitchen or fitness studio can need more capacity than a plain office of the same size.
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Glass, sun, ceilings and doors
Large glass fronts, west facing windows and poor shading bring in extra heat, especially in Indian summers. High ceilings mean more air to cool. Doors that open often to the outside or to a hot corridor keep letting warm air back in.
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Local climate and floor
A top floor outlet in a hotter city faces more heat from the roof and higher outdoor temperatures. The same layout on a lower floor in a milder city can manage with less capacity.
What Happens When You Get Tonnage Wrong
When tonnage is far off, the costs show up quickly.
If the AC size is too low, the unit runs for long stretches, still leaves some corners warm, and the compressor works harder than it should. Breakdowns are more frequent, and the bill reflects hours of effort for only moderate comfort.
If the AC size is too high, the room cools very quickly, then the AC keeps cutting off and starting again. The air may feel cool but still slightly sticky, short bursts use more power than steady operation, and parts can wear out faster because of constant cycling.
A Simple Way to Talk Sizing With Your Vendor
You do not have to calculate everything yourself, but you can walk into the discussion prepared.
Before you ask for quotes, do three small things for each room or zone:
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Measure the area
Note the size in sq. ft. for each cabin, shop floor, salon room, office bay or gym studio.
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Note people and heat sources
Write down how many people are usually in that space during busy hours and list the main heat sources. For example ovens, refrigerators, treadmills, cardio machines, computers, bright lighting.
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Mark glass, sun and doors
Mark any large glass, west facing walls and doors that open often to the outside or to a hot corridor.
This is usually enough to sense whether a number feels reasonable and to question quotes that ignore how your space actually runs in peak hours.
Keep Comfort and Cost in Balance
Do not guess tonnage or leave it entirely to someone else. Use floor area, typical occupancy and the main heat sources in each room to arrive at a rough range, then see if it lines up with the basic sizes in this guide. Get the capacity roughly right, choose a 5 star BEE rated system and make sure it is serviced and checked regularly. That is usually enough to keep your rooms comfortable in peak hours without paying for more cooling than you need.
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