# How to calculate BTU per square foot

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An air conditioner's capacity to cool air is measured in British Thermal Units (BTUs). Air conditioners have two functions: to cool a room and to remove humidity. Installing an air conditioner larger than the appropriate size will leave the occupant feeling uncomfortable since it will not be able to remove enough humidity for its cooling rate. Use the following steps to determine what capacity BTU air conditioner is required for your room's square footage.

Skill level:
Easy

### Things you need

• Measuring tape
• Pencil
• Calculator

## Instructions

1. 1

Measure the length of the intended room. Note this measurement down on your notepad.

2. 2

Measure the width of the intended room. Note this measurement down on your notepad.

3. 3

Multiply the measurement of the length by the width. This number will be the square footage of the room.

4. 4

Compare the square footage of the intended room to the list of recommendations by the U.S. Department of Energy for air conditioner BTU capacity. The recommended capacity size can be found Resources section. Match your room's square feet to the proper BTU listed.

5. 5

Make adjustments based on the following criteria. If the room is shady, increase capacity by 10 per cent. If the room is sunny, decrease the capacity by 10 per cent. If the room is a kitchen, add 4,000 BTU and if more than two people will occupy the room then add 600 BTU for each additional occupant.

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