Sizing a MovinCool Portable Air Conditioner

Proper air conditioner sizing is essential for successful cooling. MovinCool air conditioners that are too small will not provide adequate cooling, while units that are too large may cool the room too rapidly.

A MovinCool portable air conditioner's size, or cooling capacity, is rated in BTU’s per hour. A single BTU (British Thermal Unit) is the amount of energy required to raise the temperature of one pound of water one ºF over a one hour time span. Portable air conditioners are also commonly rated in what are referred to as tons of cooling. This does not refer to the unit's weight but its cooling capacity. A one ton MovinCool portable air conditioner simply means that it has a cooling capacity of 12,000 BTUs. By extension, a two ton unit has a capacity of 24,000 BTUs, a five ton unit has a capacity of 60,000 BTU, and so forth.

We use three primary methods to size a space for portable air conditioning:

1. Rule of thumb.
2. Replace ton for ton.
3. Heat load calculation.

Portable Air Conditioning Sizing Rule of Thumb

Portable air conditioning is often used in unexpected, unplanned or emergency rental situations. As such, we often utilize the rule of thumb method to obtain rapid yet accurate estimations. Combining practical experience with this rule of thumb produces great cooling solutions and leads to our adage “Effective air conditioning sizing is one half art and one half science."

  • Server / Computer rooms 1 ton per 200 sq.ft. to 400 sq.ft.
  • General office areas 1 ton per 400 sq. ft.
  • Hospital general areas / Labs 1 ton per 400 sq. ft.
  • Hospital MRI imaging 1 ton per 250 sq.ft.
  • High heat industrial plants 1 ton per 200 sq. ft.
  • Outdoor tents (summer time) 1 ton per 200 sq. ft.


Ton for Ton

The second sizing method is ton for ton. If you have a situation where the permanent system is being replaced, repaired, or is otherwise unavailable, using portable air conditioning of an equal cooling capacity to that of the permanent system is a great place to start. For example, if you have 10 tons of cooling serving a computer room which is now off line, looking at 10 tons of portable air conditioning as a replacement is a great place to start.

Heat Load Calculation

The third method is heat load calculation. A Mobile Air representative will visit your facility to complete a survey of the area requiring cooling. Some of the factors used in a heat load calculation are:

  • The physical size of the space to be cooled including the ceiling height and the shape or lay-out of the space.
  • The climate zone of the location.
  • Insulation values of the area being cooled.
  • Number, size, and location of windows and skylights.
  • Survey of heat generating items such as lighting, computers, printers, kitchens, people, processes, etc.
  • Outside air requirements entering the building.


Our MovinCool portable air conditioner specialists are happy to help you to properly size your system. Call us at (888) 474-4340 or visit our contact page to learn more about sizing a MovinCool air conditioner.

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