Free Air Conditioner Size Calculator

Determine the right air conditioner capacity in BTUs for a room based on its square footage.

sq ft

Recommended BTU

7,000 BTU

In Tons0.58 tons

Recommended BTU vs Room Area

How to Size an Air Conditioner

The general rule is 20 BTU per square foot. Adjust for sun exposure and occupancy.

Formula

Base BTU = Room Sq Ft x 20

Adjustments: +600 BTU per person over 2, +10% for sunny rooms, -10% for shaded.

1 ton = 12,000 BTU.

Example Calculation

350 sq ft room, average sun, 2 occupants.

  1. 01Base BTU = 350 x 20 = 7,000
  2. 02Occupant adjustment = 0 (2 or fewer)
  3. 03Sun factor = 1.0 (average)
  4. 04Recommended BTU = 7,000 x 1.0 = 7,000 BTU
  5. 05In tons = 7,000 / 12,000 = 0.58 tons

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