Window AC BTU Calculator
Find your room’s square footage in ENERGY STAR’s cooling capacity chart, then adjust for sun, shade, extra people and kitchens. The result is the BTU per hour to look for. The chart assumes an 8-foot ceiling.
Calculate
Enter your numbers to see the result. Without JavaScript, use the official table below.
The official table
ENERGY STAR’s cooling capacity chart (8-foot ceiling):
| Area to be cooled (sq ft) | Capacity needed (BTU/h) |
|---|---|
| 100 up to 150 | 5,000 |
| 150 up to 250 | 6,000 |
| 250 up to 300 | 7,000 |
| 300 up to 350 | 8,000 |
| 350 up to 400 | 9,000 |
| 400 up to 450 | 10,000 |
| 450 up to 550 | 12,000 |
| 550 up to 700 | 14,000 |
| 700 up to 1,000 | 18,000 |
| 1,000 up to 1,200 | 21,000 |
| 1,200 up to 1,400 | 23,000 |
| 1,400 up to 1,500 | 24,000 |
| 1,500 up to 2,000 | 30,000 |
| 2,000 up to 2,500 | 34,000 |
ENERGY STAR’s adjustments: reduce capacity by 10 percent if the room is heavily shaded; increase it by 10 percent if the room is very sunny; add 600 BTU/h for each person beyond two who regularly occupy the room; add 4,000 BTU/h if the unit is used in a kitchen.
How the result is worked out
The base capacity is the chart row that contains your area (areas outside 100–2,500 sq ft are outside the chart). Adjustments are applied exactly as ENERGY STAR lists them. The model list shows ENERGY STAR certified window air conditioners whose rated BTU/h is at least the result, starting from the closest; it is an ordering, not a recommendation.
Full shortlists
- 5,000 BTU Window Air Conditioners
- 6,000 BTU Window Air Conditioners
- 8,000 BTU Window Air Conditioners
- 10,000 BTU Window Air Conditioners
- 12,000 BTU Window Air Conditioners
- 14,000 BTU Window Air Conditioners
- 18,000 BTU Window Air Conditioners
- 24,000 BTU Window Air Conditioners
- Air Conditioners with Heating and Cooling
- Energy-Efficient Air Conditioners
- ENERGY STAR Most Efficient Air Conditioners
- High-CEER Window Air Conditioners (16+)
- 230-Volt Window Air Conditioners
- Lighter Window ACs (45 Lb or Less)
- Narrow Window ACs (18 Inches Wide or Less)
- Midea Window Air Conditioners
- TCL Window Air Conditioners
Sources
Model specs: ENERGY STAR product data (data.energystar.gov, updated 2026-11-06). We compile and compare published data; we do not run our own product tests. See How We Compare.