BTU Chart: Heating & Cooling by Room Size
Cooling BTU Chart (by Room Size)
Based on ASHRAE Climate Zone 4 (e.g., New York, Denver). For Zone 1-2 (hot), multiply by 1.3. For Zone 5-6 (cold), multiply by 0.8.
| Room Size | 8-ft Ceiling | 9-ft Ceiling | 10-ft Ceiling | AC Size |
|---|---|---|---|---|
| 100 sq ft (10×10) | 2,000 BTU | 2,250 BTU | 2,500 BTU | Mini-split or window |
| 150 sq ft (10×15) | 3,000 BTU | 3,375 BTU | 3,750 BTU | Mini-split |
| 200 sq ft (14×14) | 4,000 BTU | 4,500 BTU | 5,000 BTU | Mini-split / window |
| 250 sq ft (16×16) | 5,000 BTU | 5,625 BTU | 6,250 BTU | Mini-split / window |
| 300 sq ft (17×18) | 6,000 BTU | 6,750 BTU | 7,500 BTU | 0.5 ton |
| 400 sq ft (20×20) | 8,000 BTU | 9,000 BTU | 10,000 BTU | 0.75 ton |
| 500 sq ft (22×23) | 10,000 BTU | 11,250 BTU | 12,500 BTU | 1 ton |
| 750 sq ft | 15,000 BTU | 16,875 BTU | 18,750 BTU | 1.5 ton |
| 1,000 sq ft | 20,000 BTU | 22,500 BTU | 25,000 BTU | 2 ton |
| 1,500 sq ft | 30,000 BTU | 33,750 BTU | 37,500 BTU | 2.5–3 ton |
| 2,000 sq ft | 40,000 BTU | 45,000 BTU | 50,000 BTU | 3.5–4 ton |
| 2,500 sq ft | 50,000 BTU | 56,250 BTU | 62,500 BTU | 4–5 ton |
| 3,000 sq ft | 60,000 BTU | 67,500 BTU | 75,000 BTU | 5 ton |
Heating BTU Chart (by Room Size)
Based on ASHRAE Climate Zone 4 (moderate cold). For Zone 1-3 (warm), multiply by 0.6. For Zone 5-6 (cold), multiply by 1.4.
| Room Size | 8-ft Ceiling | 9-ft Ceiling | 10-ft Ceiling | Climate Zone |
|---|---|---|---|---|
| 100 sq ft | 4,000 BTU | 4,500 BTU | 5,000 BTU | Zone 4 (moderate) |
| 150 sq ft | 6,000 BTU | 6,750 BTU | 7,500 BTU | Zone 4 |
| 200 sq ft | 8,000 BTU | 9,000 BTU | 10,000 BTU | Zone 4 |
| 300 sq ft | 12,000 BTU | 13,500 BTU | 15,000 BTU | Zone 4 |
| 400 sq ft | 16,000 BTU | 18,000 BTU | 20,000 BTU | Zone 4 |
| 500 sq ft | 20,000 BTU | 22,500 BTU | 25,000 BTU | Zone 4 |
| 1,000 sq ft | 40,000 BTU | 45,000 BTU | 50,000 BTU | Zone 4 |
| 1,500 sq ft | 60,000 BTU | 67,500 BTU | 75,000 BTU | Zone 4 |
| 2,000 sq ft | 80,000 BTU | 90,000 BTU | 100,000 BTU | Zone 4 |
| 2,500 sq ft | 100,000 BTU | 112,500 BTU | 125,000 BTU | Zone 4 |
How to Use These Charts
- Find your room size in the left column
- Match your ceiling height — use 8-ft column for standard ceilings
- Adjust for climate zone: Zone 1-2 (hot): cooling ×1.3. Zone 5-6 (cold): heating ×1.4. Zone 7-8: heating ×1.8
- Adjust for insulation: New construction (well-insulated): ×0.8. Old home (poor insulation): ×1.3
- Round up to the nearest standard equipment size
For precise calculations with all factors considered, use our BTU calculator or cooling load calculator.
Step-by-Step Example
Scenario: 400 sq ft living room, 9-ft ceiling, in Houston TX (Zone 2), standard insulation, 2 south-facing windows.
Step 1: Base cooling = 400 × 22 BTU/sq ft (Zone 2) = 8,800 BTU/h
Step 2: 9-ft ceiling → × 1.125 = 9,900 BTU/h
Step 3: South-facing windows → × 1.15 = 11,385 BTU/h
Result: ~11,400 BTU/h cooling. A 12,000 BTU (1-ton) unit is appropriate.
Common Mistakes
- Using the chart without climate adjustment: A 500 sq ft room in Miami needs 30% more cooling than the same room in Seattle
- Ignoring internal heat gains: A home office with 2 computers and 2 monitors adds ~2,000 BTU/h of cooling load
- Not accounting for occupancy: Each person adds ~600 BTU/h. A family room with 5 people needs 2,400 BTU more than the chart shows
Frequently Asked Questions
How many BTU for a 500 sq ft room?
For cooling in a moderate climate: 10,000–12,000 BTU (1 ton). For heating: 17,500–25,000 BTU. In hot climates, add 25% for cooling. In cold climates, add 50% for heating.
How many BTU for a 1,000 sq ft space?
Cooling: 20,000–24,000 BTU (1.7–2 tons) in moderate climate. Heating: 35,000–50,000 BTU. Assumes 8-ft ceilings and standard insulation.
How many BTU for a 2,000 sq ft house?
Cooling: 40,000–48,000 BTU (3.3–4 tons). Heating: 70,000–100,000 BTU. Varies significantly by climate zone and insulation quality.