What Size Air Conditioner Do I Need for 700 Sq Ft?
700 sq ft is the widest small-chart jump: 14,000 BTU/hr on one side and 18,000 on the other.
Full breakdown: BTU per square foot.
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Capacity from the chart
| Area to be cooled | Capacity needed | Source |
|---|---|---|
| 550 up to 700 sq ft | 14,000 BTU/hr | ENERGY STAR |
| 700 up to 1,000 sq ft | 18,000 BTU/hr | ENERGY STAR |
Most boundaries on this chart step by 1,000 BTU/hr. This one steps by 4,000, because 18,000 − 14,000 = 4,000. That is the same count as the kitchen adder, which is why the two get confused. A sunny 700 sq ft living area that is not a kitchen takes the 18,000 row and stops. A kitchen that is shaded and still belongs on the 14,000 row adds 4,000 and also lands at 18,000 BTU/hr. Same landing, different reason. Do not take the higher row and the kitchen adder unless both are true.
How to size it
Make the row choice out loud before you touch a percent. Shaded and two or fewer people: 14,000. Very sunny, or more than two people regularly: 18,000. Then use the table.
| Adjustment | On the 14,000 row | On the 18,000 row | Source |
|---|---|---|---|
| Heavily shaded, reduce capacity 10% | 14,000 − 10% = 12,600 BTU/hr | 18,000 − 10% = 16,200 BTU/hr | ENERGY STAR |
| Very sunny, increase capacity 10% | 14,000 + 10% = 15,400 BTU/hr | 18,000 + 10% = 19,800 BTU/hr | ENERGY STAR |
| Each additional person beyond two | 14,000 + 600 BTU/hr = 14,600 BTU/hr | 18,000 + 600 BTU/hr = 18,600 BTU/hr | ENERGY STAR |
| Unit used in a kitchen | 14,000 + 4,000 BTU/hr = 18,000 BTU/hr | 18,000 + 4,000 BTU/hr = 22,000 BTU/hr | ENERGY STAR |
10% of 14,000 BTU/hr is 1,400 BTU/hr (14,000 × 10%).
10% of 18,000 BTU/hr is 1,800 BTU/hr (18,000 × 10%).
The honest shaded case is 14,000 − 10% = 12,600 BTU/hr. The honest sunny case is 18,000 + 10% = 19,800 BTU/hr. One extra person on the upper row is 18,000 + 600 = 18,600 BTU/hr. Kitchen on the lower row is 14,000 + 4,000 = 18,000 BTU/hr. Kitchen on the upper row is 18,000 + 4,000 = 22,000 BTU/hr, and that last figure is only for a space that earned the higher row and is also a kitchen.
ENERGY STAR's oversizing line is aimed at the shortcut of buying 18,000 for a shaded room: "An oversized air conditioner costs more to purchase, wastes energy and does not provide better cooling." A unit that is too big also cools the room before it removes humidity.
Both rows assume an 8-foot ceiling. A higher ceiling means a higher CADR, in the chart note, not a silent third capacity between 14,000 and 18,000.
18,000 BTU window air conditioners on Amazon Window air conditioner support brackets on Amazon
Related questions
- What size air conditioner for 600 sq ft
- What size air conditioner for 800 sq ft
- What size air conditioner for a 500 sq ft room
All of these questions are listed on the topic map.
Sources
- ENERGY STAR, Room Air Conditioners — https://www.energystar.gov/products/room_air_conditioners — accessed Oct 2, 2026.
Frequently asked questions
What size air conditioner for 700 sq ft?
550 up to 700 sq ft is 14,000 BTU/hr, and 700 up to 1,000 sq ft is 18,000 BTU/hr. Heavy shade is the reason to use 14,000. A very sunny space, or more than two people regularly, is the reason to use 18,000.
Why is the 700 sq ft choice so large?
18,000 minus 14,000 is 4,000 BTU/hr. That gap equals the kitchen adjustment of 4,000 BTU/hr, but the two moves are not interchangeable. Jumping rows because the space is sunny is not the same fact as a unit used in a kitchen.
What does heavy shade do if I correctly stay on 14,000?
Reduce 14,000 by 10%. Ten percent of 14,000 is 1,400, so the shaded target is 12,600 BTU/hr. Starting at 18,000 instead would skip both the row choice and that reduction.
Does 18,000 BTU/hr mean I should buy a central system from this chart?
No. Both numbers are room air conditioner capacities on an 8-foot ceiling. A whole-house system needs a load calculation on the HVAC load calculator. Higher ceilings: select a room air conditioner with a higher CADR.