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.
This BTU size chart for heating and cooling covers both: find the room area in the table, pick the climate zone, and the chart shows the BTU range you need for a furnace, boiler, or AC.
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.