How many BTU's Do I Need for My Room?
This chart may help you determine what size portable air conditioner shop for. A word of caution: don't buy an air conditioner that's too large. An oversized air conditioner is actually less effective - and can waste valuable energy at the same time. Because portable air conditioners remove both heat and humidity from the air, an oversized unit will cool the room quickly, but only remove some of the humidity. This will leave your room with a damp, clammy feeling. A properly sized unit will effectively remove humidity as it cools.
To figure out which size Air Conditioner is best for your cooling needs:
1. Determine the square footage of the area to be cooled using the following formulas:
- For square and rectangular rooms, multiply the length of the area by its width - L x W
- For a triangular area, multiply the length of the area by the width and divide by 2 - L x W / 2
2. Using the square footage and the chart below, determine the correct cooling capacity. Cooling capacity is measured in British thermal units (BTUs) per hour.
|Area To Be Cooled (square feet)||Capacity Needed (BTU's per Hour)|
|100 to 150||5,000|
|150 to 250||6,000|
|250 to 300||7,000|
|300 to 350||8,000|
|350 to 400||9,000|
|400 to 450||10,000|
|450 to 550||12,000|
|500 to 700||14,000|
|700 to 1,000||18,000|
3. Make any adjustments for the following circumstances:
- If the room is heavily shaded, reduce capacity by 10 percent.
- If the room is very sunny, increase capacity by 10 percent.
- If more than two people regularly occupy the room, add 600 BTUs for each additional person.
- If the unit is used in a kitchen, increase capacity by 4,000 BTUs.
- Consider where you install the unit. If you are mounting an air conditioner near the corner of a room, look for a unit that can send the airflow in the right direction.