AC Size Calculator
Determine the air conditioner size for a space.
How It Works
BTU = Area × 20 × (Ceiling ÷ 8) × Sun factor × Insulation factor. Tons = BTU ÷ 12,000.
Example
500 sq ft with strong sun and poor insulation: 500 × 20 × 1.2 × 1.15 = 13,800 BTU ≈ 1.2 tons.
Frequently Asked Questions
What does "ton" mean in AC?
One ton equals 12,000 BTU/hour — the cooling capacity of one ton of ice melting per day.
What size AC do I need?
A quick rule is 1 ton per ~500–600 sq ft of well-insulated space; this calculator refines that.
Is bigger better?
No — an oversized unit short-cycles and fails to dehumidify. Size to the actual load.