The Most Energy Efficient Air Conditioners For 2012

by Nicola Temple on April 18, 2012

With summer just around the corner, it’s time to look at the most energy efficient air conditioners on the market for 2012.

After all, heating and cooling your home can make up about 50% of your energy bill, so investing in efficient air conditioning is economically wise as well as environmentally friendly.

I’ve looked at all the air conditioners that have achieved the ENERGY STAR efficiency rating through the US Environmental Protection Agency and listed the most efficient model for each style and size class. I’ve done this for small room units as well as central air conditioning units.

When comparing different air conditioners, there are two main measures to consider. First, each unit is given an objective measure of efficiency called the Energy Efficiency Rating (EER).  A larger EER means the unit is more efficient.

The second important measure between air conditioners is their cooling capacity. This is measured in British Thermal Units per hour (Btu/h or BTU) and essentially describes the power of the air conditioner; the higher this value, the greater the cooling capability of the unit.

As well as splitting the air conditioners up into room and unit styles, I’ve further divided the room air conditioners up into different window styles, through-the-wall style and the most efficient unit that has a heating function (reverse cycle).  These are further divided into capacity ranges based on divisions predefined by ENERGY STAR.

All units listed are current as of January 2011 and a * in the model number means that any number or letter may fall in that position. If there is nothing listed for a particular capacity class, this is because there are no ENERGY STAR qualified models of this style within that capacity range.


To be ENERGY STAR qualified, room units must use 10% less energy than non-qualified units.

Window Air Conditioners:

These units have louvered sides to help fit them into a window opening. They vent air through the sides and back of the unit. They are not meant to be used as built-in units.

energy efficient air conditioners

Energy efficient air conditioners, such as this Friedrich model, have to use 10% less energy than standard models to qualify for the ENERGY STAR label.


These models are designed for mounting in a casement window; in other words, windows that are hinged to their frame.

<6,000 BTU = Two Friedrich models tie for this capacity category, each with 5,800 BTU and an EER of 11. The model numbers are SQ06N10-A and XQ06M10A.

6,000-7,999 BTU = The Friedrich SS08N10 comes out on top with 7,900 BTU and EER=11.7.

8,000-13,999 BTU = Frigidaire FRA125ZU1 – 12,000 BTU and EER=11.8.

14,000-19,999 BTU = Friedrich SM15M10-A and SM15N10 – both with 14,800 BTU and EER=10.9.

20,000+ BTU = There are a number of GE models that range between 23,900-24,200 BTU and all have an EER of 10.8. The models are:

  • AEH24DQ**
  •  AEL24DQ**
  •  AEM24DQ**
  • AEW24DQ**
  •  AEZ24DQ**


This style of air conditioner has an encased assembly designed for mounting in a sliding or casement window.

<6,000 BTU = Whirlpool W5WCE055YW0 – 5,500 BTU and EER=11.

6,000-7,999 BTU = Whirlpool W5WCE065YW0 and W7WCC065YB0 – 6,300 BTU and EER=11.1.

8,000-13,999 BTU = There are four Whirlpool models all tied for first in this category with an EER of 11. Two have an 8,000 BTU capacity, W5WCE085YW0 and W7WCC085YB0, and two have a 10,000 BTU capacity, W5WCE105YW1 and W7WCC105YB1.

Through-The-Wall or Built-In Air Conditioners:

These units do not have louvered sides and they vent through the back only.

6,000-7,999 BTU: GE AJCQ06LCE** – 6,500 BTU, EER=10.4.

8,000-13,999 BTU: There are a number of makes and models that all tie with an EER of 9.8:

  • GE AJCM08ACE** and AJCQ08ACE**each with 8,200 BTU
  • Fedders AZ7A09W2A – 9,200 BTU
  • GE AJCQ09DCE**- 9,300 BTU
  • GE AJCQ09DCE** – 9,600 BTU
  • GE AJCM10DCE** and AJCQ10DCE** – 10,000 BTU
  • GE AJCQ10DCE** and AJCM10DCE** – 10,300 BTU
  • GE AJCM10ACE** and AJCQ10ACE**- 10,400 BTU
  • Fedders AZ7A12W7A and GE AJCM12DCE** and AJCQ12DCE** – 11,800 BTU
  • GE AJCM12DCE**, AJCQ12DCE**, and AJCQ10ACE** – 12,000 BTU

20,000+ BTU:  There are two models that tie with an EER of 9.4; the Arctic King MWK-25CRN1-MI4 with a 25,000 BTU capacity and Keystone KSTAW22A with 22,000 BTU capacity.

Reverse Cycle Air Conditioners:

The most energy efficient air conditioner with a heating unit is the Friedrich YS10N10, with a 9,500 BTU capacity and an EER of 11.7. It has louvered sides for fitting in a window.


ENERGY STAR qualified central air conditioners are 14% more efficient than standard models. As well as EER, they are also given a Seasonal Energy Efficiency Ratio (SEER), which can be compared across units.

It’s important to realize, however, that a central air conditioning unit will only work to specified performance with a newer furnace. It is highly recommended that you replace your furnace with a more efficient system if your furnace is over 15 years old.

The top three models in this category are all air-source heat pumps (ASHP) with an electric furnace or fossil fuel heating system (a standard split system):

1)      Fujitsu ASU9RLS2/AOU9RLS2 – SEER = 30.36, EER=16.83, Capacity = 9,000 BTU

2)      Fujitsu ASU12RLS2/AOU12RLS2 –SEER=28.77, EER=15.13, Capacity = 12,000 BTU

3)      GREE GWH09TB-D3DNA1A/1 - SEER= 26.67, EER=15.74, Capacity = 9,000 BTU

If you are out shopping for energy efficient air conditioners, it’s important to know what capacity you need before you go so that you can buy an air conditioner that is properly sized for your needs.  Just because a unit is bigger doesn’t mean it will be better at cooling, it could actually be less efficient.

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