What size air conditioner for a 10x10 room?
Your room, your adjustments
A 10x10 room with each ENERGY STAR adjustment
| 10 x 10 room (100 sq ft) | BTU/h |
|---|---|
| Chart size, normal sun, up to 2 people | 5,000 |
| Heavily shaded (−10%) | 4,500 |
| Very sunny (+10%) | 5,500 |
| 3 regular occupants (+600) | 5,600 |
| Used as a kitchen (+4,000) | 9,000 |
Arithmetic on the ENERGY STAR Room Air Conditioners chart and adjustments, 8 ft ceilings.
10x10 vs 12x12: same unit, different position in the row
A 10 x 10 room is 100 sq ft, exactly where ENERGY STAR's table starts. A 12x12 room is 144 sq ft, near the 150 sq ft top of the same row. Both land on 5,000 BTU/h because that row covers everything from 100 up to 150 sq ft. The chart does not list a smaller size, so a room under 100 sq ft is below the table rather than in a smaller row.
The difference is what pushes you out of the row. In a 10 x 10 room, normal sun and two people stay at 5,000 BTU/h. The adjustments are what move the number: a sunny window takes it to 5,500 BTU/h, and a kitchen takes it to 9,000 BTU/h. For a room right at the 150 sq ft line, see the 150 sq ft page.
ENERGY STAR room AC sizing table
| Area to be cooled | Capacity needed |
|---|---|
| 100 up to 150 sq ft | 5,000 BTU/h |
| 150 up to 250 sq ft | 6,000 BTU/h |
| 250 up to 300 sq ft | 7,000 BTU/h |
| 300 up to 350 sq ft | 8,000 BTU/h |
| 350 up to 400 sq ft | 9,000 BTU/h |
| 400 up to 450 sq ft | 10,000 BTU/h |
| 450 up to 550 sq ft | 12,000 BTU/h |
| 550 up to 700 sq ft | 14,000 BTU/h |
| 700 up to 1,000 sq ft | 18,000 BTU/h |
| 1,000 up to 1,200 sq ft | 21,000 BTU/h |
| 1,200 up to 1,400 sq ft | 23,000 BTU/h |
| 1,400 up to 1,500 sq ft | 24,000 BTU/h |
| 1,500 up to 2,000 sq ft | 30,000 BTU/h |
| 2,000 up to 2,500 sq ft | 34,000 BTU/h |
Source: ENERGY STAR Room Air Conditioners (8 ft ceilings). Machine-readable copy: ENERGY STAR sizing data.
This is a room-unit chart, not a whole-house load calculation. For a rule of thumb by area, see how many BTU per square foot. Portable units are rated differently; see portable air conditioner sizing.