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Quick Facts on Room Air Conditioners

Today's air conditioners are about 20 percent more energy efficient than they were in 1990, and ENERGY STAR® qualified models are even better.

New coil designs and more efficient compressors have contributed greatly to the improved efficiency of room air conditioners.

The majority of room air conditioners are the window-mounted, louvered type. They are mounted into an open window and plugged in. As the size increases, the amount of electricity required increases and the customer may have to be concerned with having a dedicated electrical circuit, or installing a 240-volt circuit for the larger sizes.


Room air conditioners British thermal
unit per hour
(Btu/h)
1990
(minimum
EER)
2003
(minimum
EER)
ENERGY STAR
qualified
Window-mounted units
(with louvred1 sides), without reverse cycle2
less than 6000
6000 to 7999
8000 to 13 999
14 000 to 19 999
8.0
8.0
8.0
8.0
9.7
9.7
9.8
9.7
10.7
10.7
10.8
10.7
Through-the-wall units
(with non-louvered3 sides),
without reverse cycle2
less than 6000
6000 to 7999
8000 to 13 999
14 000 to 19 999




9.0
9.0
8.5
8.5
9.9
9.9
9.4
9.4
Casement only
Casement slide
All sizes

8.7
9.5
9.6
10.5
These are the most common air conditioners, but there are other designs and larger sizes.
1 Has exterior side vents.   2 No heating provided.   3 No exterior side vents.  

Some room air conditioners are designed to fit through-the-wall (TTW). These are also referred to as "without louvered sides" and are built this way because the wall framing would interfere with the airflow through the sidewalls of the air conditioner. TTW room air conditioners tend to be less efficient than the regular window units. TTW room air conditioners must also meet minimum efficiency regulations. Work is underway to include TTW units in the ENERGY STAR specifications.

Although not common in colder climates, some room air conditioners are built to provide some heating, either with electric resistance heating or by what is called a reverse cycle. Reverse cycle means the room air conditioner acts like a heat pump and will heat the room. When the flow of the refrigerant is reversed, heat is released inside.

Window-mounted units are labelled on the EnerGuide label as being louvered, i.e., having exterior side vents. This permits better air exchange, which is in part why the minimum regulatory and ENERGY STAR required performance levels are higher for window-mounted units than for TTW units that are non-louvered (without louvered sides).

Portable room air conditioners are now also available. They have a hose that is used to exhaust heat to the outside and, because they are on wheels, can be moved from room to room. Water condensed from the cooled air has to be removed and drained away. There is currently no CSA Standard or energy efficiency rating for this product.

Testing today (CSA Standard C368.1-M90)

Note: This test standard is also used as the basis for verifying energy performance for ENERGY STAR qualified products.

Room air conditioners are tested in order to get an Energy Efficiency Ratio (EER), which is calculated by dividing output cooling capacity in British thermal units per hour (Btu/h) by the power input in watts (W).

The test consists of the following steps:

  • Two rooms are used to simulate the inside and the outside of the house.
  • The room air conditioner is installed in the wall between the two rooms.
  • Heat and moisture are added to the inside room.
  • The heat and moisture removed by the room air conditioner are measured, along with electricity use.
  • The EER is calculated.

Calculating the EnerGuide Rating

The cooling capacity is divided by the energy consumption during the test period. This is the EER value on the EnerGuide label.

For example:

6000 Btu/h(cooling capacity)
560 W (electrical power)
= 10.7 EER



ENERGY STAR

ENERGY STAR High Efficiency Symbol
ENERGY STAR qualified room air conditioners are the best performers

ENERGY STAR qualified room air conditioners Room air conditioners that display the ENERGY STAR symbol must exceed minimum regulated energy efficiency standards by 10 percent or more.

Features that help room air conditioners achieve this efficiency include

  • high-efficiency compressors
  • high-efficiency fan motors
  • improved heat transfer surfaces

The ENERGY STAR name and the ENERGY STAR symbol are registered trademarks of the United States Environmental Protection Agency and are used with permission.