# How to Calculate the Room Size for an Air Conditioner

The size and type of air conditioner needed depends on the size of space you are trying to cool. An air conditioner that is too large will cool the air too quickly and will not correctly handle the humidity level. An air conditioner that is too large also will have a tendency to turn on and off more often than really need, creating undo wear on the unit. An air conditioner that is too small will not be able to cool the air sufficiently. It will have a tendency to be overworked, creating undue wear on the unit.

1. Measure the space you will be cooling with a tape measure. Find the length and width of the space.

2. Multiply the length and width together for each room.

3. Add each room's total together to get the total area to be cooled by an air conditioner.

4. Do not forget to measure large bathrooms, entryways and hallways. These spaces will also need to be cooled.

5. Divide the total area of the space that you are attempting to cool by 500 if it is residential and 400 if it is commercial. The result is the number of tons you will need for your air conditioner. For example, if your residential space is 2,500 square feet, dividing 2,500 by 500 equals 5 tons needed.