What Size Air Conditioner Do You Need?
Getting the tonnage right matters more than the brand — here's how to think about it.
As a rough starting point, a small bedroom (under 120 sq ft) often suits a 1 ton AC, a medium room (120–180 sq ft) often suits 1.5 ton, and a larger room (180–250 sq ft) often suits 2 ton — but sun exposure, ceiling height, and how many people usually use the room can shift this up or down. Treat this as a starting point, not a rule; we'll confirm the right size for your actual room when you visit.
Getting AC size wrong is one of the most common and costly buying mistakes. An undersized AC runs almost constantly and still struggles to cool the room. An oversized AC cools too fast without running long enough to properly remove humidity, which can leave a room feeling cold but clammy — and it costs more upfront for no benefit.
Our category page covers what we stock. This guide covers how to actually choose the right size, plus the split-versus-window and inverter decisions that come with it.
How to estimate the AC tonnage you need
Start with your room's floor area, then adjust for conditions that make a room harder or easier to cool. Rooms with strong afternoon sun, top-floor rooms directly under an uninsulated roof, or rooms with heat-generating equipment (like a kitchen) generally need more capacity than the basic area alone suggests.
Ceiling height matters too — a room with a higher-than-standard ceiling has more air volume to cool, even if the floor area is the same as a lower-ceilinged room. And a room that regularly holds more people needs a bit more capacity to offset the body heat.
Split vs window: which fits your situation
Split AC
- Needs an outdoor unit and space to mount it, plus piping between indoor and outdoor units
- Generally quieter indoors, since the compressor sits outside
- More flexible about where the indoor unit goes on the wall
- Usually a higher installation cost due to the piping and mounting work
Window AC
- Needs a window or wall opening sized for the unit, with a clear path to vent hot air outside
- The compressor is in the same box as the room unit, so it's louder indoors
- Simpler, faster installation in most cases
- Usually the lower-cost option for the same cooling capacity
Is inverter worth it for your usage?
Inverter ACs adjust compressor speed to hold a steady temperature, rather than switching fully on and off. The running-cost savings scale with how many hours a day the AC runs — not with the room size or the AC's price.
If the AC only runs occasionally, for a couple of hours here and there, the extra upfront cost of an inverter model may take a long time to pay back. If it runs most of the day or night — a bedroom AC used every night, or a shop running AC through business hours — the efficiency gains compound faster and typically pay back sooner.
Key decision factors
Room area and ceiling height
Bigger floor area and higher ceilings both mean more air volume to cool, pushing you toward a larger tonnage.
Sun exposure and floor level
West-facing rooms and top-floor rooms under a direct roof tend to need extra cooling capacity beyond the basic area calculation.
How many people use the room
More people in a room adds body heat the AC needs to offset, which can nudge you toward the next size up.
How many hours a day it runs
The more hours the AC runs daily, the more an inverter's running-cost savings compound over time.
Space for the outdoor unit
A split AC needs somewhere to mount its outdoor unit — check this before deciding between split and window.
Installation feasibility
A window AC needs a suitable window or wall opening with a clear vent path outside — not every room has one.
Common mistakes to avoid
Buying the biggest tonnage ‘to be safe’
An oversized AC cools the room too fast without running long enough to properly dehumidify, which can leave it feeling cold but clammy.
Ignoring sun exposure and floor level
Two rooms of the same size can need different tonnage if one gets direct afternoon sun or sits under an uninsulated roof.
Choosing window AC without checking the vent path
Not every window or wall opening can safely vent a window AC's exhaust — confirm this before you commit to the cheaper option.
Assuming inverter always pays for itself
If the AC only runs occasionally, the extra upfront cost of an inverter model may not be worth it — it depends on your actual hours of use.
Frequently asked questions
Ready to choose?
See the split, window and inverter ACs we carry, with real brand options.
Still not sure?
Message us on WhatsApp with your specific situation and we'll help you think it through.