What should I consider for when buying a room air conditioner?
Remember that bigger is not always better! An oversized air conditioner is less effective, wastes energy and does not provide better cooling. When installing your new unit, be sure to follow the instructions in the manual and use the included insulation materials. An improperly installed room AC leaks as much as a 6 sq. in. hole! For maximum savings, set the AC thermostat as high as is comfortable.
Room air conditioners with Variable Speed Technology
Consider purchasing a room air conditioner with variable speed compressor technology. In a conventional room air conditioner, the compressor works either at maximum capacity when the room thermostat calls for cooling or off when the desired temperature has been achieved, typically alternating frequently between full on and off. Room air conditioners with efficient variable speed compressors can vary the speed of the internal compressor motor in order to continuously control the temperature. As a result, the capability for efficient variable output allows a room air conditioner to quietly regulate the temperature and save a significant amount of energy during operation.
Properly Sized Room Air Conditioners
Room air conditioner sizing is all about matching the room size to the air conditioner size. A unit that is too big will be less effective and offer reduced air conditioner efficiency. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room before it has a chance to remove the humidity. The result will be a room that's not very comfortable because cool moist air will make the room feel damp and clammy.
The most energy efficient air conditioner is sized to the square footage of the space to be cooled. Getting the right size means getting the comfort and the energy efficiency right.
1. Determine the room's square footage
Determining the floor square footage of the area to be cooled takes simple math. Just use the following formulas.
9 in = .75 ft.
6 in = .5 ft.
3 in = .25 ft.
Always measure in feet, converting the inches to fractions of a foot
For example: 12 ft., 6 inches, is 12.5 ft.
Square and rectangular rooms:
Multiply the full length of the room by its width.
Triangular rooms:
Multiply the length of the area by the width and divide by two.
Complex room shapes:
Sub-divide into squares, rectangles and triangles. Then use the formulas above to determine the total square footage.
If the shape of your room is more complex, ask your sales associate where you plan to purchase your air conditioner to help you determine the square footage.
2. Find the correct cooling capacity for your room size
Using the cooling capacity chart, find your room's square footage in the "Area To be Cooled (square feet)" column, then use the "Capacity Needed (BTUs per hour)" column to choose the correct cooling capacity for your room air conditioner. The capacities are calculated based on an 8-foot ceiling. If you have higher ceilings, you may want to select a room air conditioner with a higher CADR. Cooling capacity is shown in British thermal units (BTUs) per hour.
Area To Be Cooled (square feet)
Capacity Needed (BTUs per hour)
100 up to 150
5,000
150 up to 250
6,000
250 up to 300
7,000
300 up to 350
8,000
350 up to 400
9,000
400 up to 450
10,000
450 up to 550
12,000
550 up to 700
14,000
700 up to 1,000
18,000
1,000 up to 1,200
21,000
1,200 up to 1,400
23,000
1,400 up to 1,500
24,000
1,500 up to 2,000
30,000
2,000 up to 2,500
34,00
3. Adjust as necessary
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.
Consider selecting a room AC with a lower Global Warming Potential refrigerant – Room air conditioners use refrigerants.
Refrigerants with lower global warming potential (GWP) for room air conditions include R-32 (HFC-32), R-454B, and R-290. Selecting an ENERGY STAR certified model
with a lower GWP refrigerant means your product will have a much lower impact on the climate if the refrigerant is released into the environment.
The GWP compares the warming power of a substance to an equivalent amount of CO2 (GWP = 1 for CO2). Some refrigerants are hydrofluorocarbons (HFCs),
which are powerful greenhouse gases with GWPs hundreds or thousands of times higher than CO2. While R-32 (HFC-32) and R-454B are HFCs, they are lower-GWP
options for room air conditioners. Select the filter below to find room air conditioners that contain refrigerants with a lower impact on global warming.
ENERGY STAR Most Efficient
Products that are recognized as ENERGY STAR Most Efficient deliver cutting edge energy efficiency along with the latest in technological innovation. They represent
the very best for energy savings and environmental protection. Most Efficient room air conditioner models are low noise. Click the Most Efficient filter to find
recognized models.
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