Unlike air conditioner units whose capacity is measured in British Thermal Units (BTUs), coolers are measured in cubic feet per minute (CFM). Whether sizing a unit to cool a single room or an entire house, the calculations are the same. The area to be cooled must be calculated in cubic feet to determine what size cooler is needed. .

Measure the width and length of the space to be cooled. Multiply the two numbers together.

Measure the height of the ceiling. Multiply the product of the calculation in Step 1 with the measured height of the ceiling.

Divide the product of the calculation in Step 2 by 2. This value is the CFM required to cool the space.

## Things You Will Need

- Calculator
- Measuring tape

## Tip

- As an example, if your house is 25 feet wide and 45 feet in length with an 8 foot ceiling, the calculations are 25 x 45 = 1125; 1125 x 8 = 9000; 9000 รท 2 = 4500. A house this size requires a cooler that is at least 4500 CFM.