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Sizing Window & Portable Room Air Conditioners

To obtain optimum cooling at the lowest energy costs the sizing of a room air conditioner, as shown in Figure 1, is critical. An air conditioner that is larger than needed will turn on and off frequently which increases energy costs and wear and tear on the air conditioner.

window air conditioner
Figure 1 - Window air conditioner

Selection of:

Window air conditioners.

Portable air conditioners.

The factors that are important are:

  • The square foot area of the room (length X width).
  • The amount of sunlight in the room.
  • The number of people normally in the room.
  • Is the room a kitchen?

Table 1 is based on 1 or 2 people occupying the room with normal sunlight (neither shaded or in direct sun).

Table 1 is based on 1 or 2 people occupying the room with normal sunlight (neither shaded or in direct sun)

Adjustments to the size of the air conditioner must be made based on additional factors:

Sunny Rooms - Add 10% to the amount of BTU's required.

Shaded Rooms - Deduct 10% from the amount of BTU's required.

Each Additional person occupying the room - Add 10% to the amount of BTU's required.