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Air conditioner size calculator

Find out how many BTU your room needs, and which standard unit size to buy, based on the room’s size, the sun, and how it’s used.

Sun and insulation

Nearest unit to buy

18,000 BTU

Cooling needed: 14,000 BTU · about 1.2 ton

A rule of thumb for hot climates like Saudi Arabia. Ceiling height, windows and insulation change the real need, so confirm with an installer for large rooms.

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How to use it

Enter the room’s length and width, choose how sunny it is, and add the number of people and whether it’s a kitchen. You’ll get the cooling needed and the nearest standard unit.

Quick guide

Room size Normal room Sunny room
12 m² (3 × 4) 9,000 BTU 12,000 BTU
16 m² (4 × 4) 12,000 BTU 18,000 BTU
20 m² (4 × 5) 18,000 BTU 18,000 BTU
30 m² (5 × 6) 24,000 BTU 24,000 BTU

Tips

  • Top-floor rooms and west-facing windows need more cooling.
  • Inverter units save energy in long Saudi summers.
  • For big spaces, two units or a central system often work better than one large unit.

See what cooling costs with the electricity bill calculator.

Air conditioner size calculator: common questions

How many BTU do I need per square meter?

In hot climates like Saudi Arabia, a common rule is 600 to 800 BTU per m², about one ton for every 15 to 20 m², depending on sun and insulation.

What does one ton mean?

One ton of cooling is 12,000 BTU per hour. An 18,000 BTU unit is 1.5 tons, and 24,000 BTU is 2 tons.

Is a bigger unit always better?

No. A unit that’s too big cools quickly but switches on and off, removes less humidity and wastes energy. Choose the nearest size above your need.

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