Refrigeration Tonnage based on Area

Cooling load for a building can be roughly estimated using a rule of thumb formula which is generally applicable in the Malaysian industry.

The concept relies on a simple formula of the Cooling Load Density (per unit area) multiplied by the Air-conditioned Area.

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Cooling load density is a very rough measure to determine the degree of cooling based on various factors and situations. Table below shows an example of the recommended cooling load density applicable for general buildings.

Cooling Load in btu/h can be related to refrigeration tonnage using the simple formula below.


The above cooling heat load is suited to a tropical climate. In actual, heat load largely subjects to other factors such as room occupancy, climate, area and directions of windows and walls, shall be appropriately simulated using heat load software such as Carrier’s E20 Design Software or Hourly Analysis Program (HAP), Trane’s Trace 700 etc.

For a slightly more detailed heat load estimation based on the same principle, go to Heat Load (& Cooling Load) for Air-Conditioning Calculator

With another rule of thumb, it is often assumed that 1 RT of cooling is optimal to cool 300 to 400 CFM of air with minimal fresh air introduction.