Result
Preliminary calculation: This tool is for quick sizing and information. In real projects, load calculation, selection and commissioning require engineering calculations and a site survey. Results are approximate values.
How is the calculation done?
The tool takes the typical cooling load per area for the space type, corrects it for ceiling height and multiplies it by the sun exposure factor. For more than two people, about 150 W per person is added, plus the equipment heat you enter.
Q = Area × base load × (height / 2.7) × sun factor + (people − 2) × 150 + equipment WThe result is given in BTU/h and kW; 1 kW is approximately 3,412 BTU/h. Because air conditioners are sold in standard nominal sizes such as 9,000, 12,000, 18,000 and 24,000, the nearest standard size up is recommended.
Things to watch when choosing capacity
- A unit that is too large cycles on and off often and does not remove humidity well
- A unit that is too small falls short in intense heat
- Increase capacity in rooms with large glass areas and strong sun
- Calculate open-plan spaces together
- Outdoor unit location and pipe length affect efficiency
- VRF or chiller systems are considered for commercial and multi-room buildings
For larger projects, see the VRF air conditioner and chiller pages.
Frequently asked questions
How many square meters can a 9000 BTU air conditioner cool?
As a rough figure, about 15-20 m² with a normal ceiling height and average sun exposure. This area shrinks for rooms with direct sun, large windows or on the top floor. You can calculate it for your own conditions with the tool.
What is BTU?
BTU/h is the unit for the amount of heat moved in one hour. 1 kW is approximately 3,412 BTU/h.
The result came out as 12,000 BTU; can I get a 9,000 BTU unit instead?
A unit below the required capacity may fall short on hot days. It is safer to choose the recommended standard capacity or the next size up.