If you have ever walked down the street in Manhattan during the summer, you probably noticed water dripping from the window air conditioners overhead.
This is a common occurrence in urban areas during the dog days of summers. So many apartment dwellers run their window air conditioners throughout the summer months.
You might be wondering, however, how energy efficient these window air conditioner units are. This also raises the question of whether it is more efficient to rely on one central air conditioning system as opposed to two or three different window units in your apartment or house.
The answers to these questions are not absolutely clear.
First, here is some background information. In the US, air conditioner use consumes 15% of our total energy usage. And the number of people with air conditioners keeps going up. Some studies indicate that 80% of Americans live in a house or apartment with an air conditioner.
If you are trying to decide which type of air conditioner to purchase, you essentially have two choices: a central system or a window unit.
Window air conditioner units are housed in one box. All of the parts the condenser, compressor, fan are in that one unit. The unit is then secured to your windowsill. Window air conditioners can only cool the room where you have installed the unit.
By contrast, central air conditioners are much different. They have two separate units. One unit, which includes the compressor and condenser is placed outside of your home. The fan or air handler is inside your home. The two units are connected through a series of ducts. Also, central air works in all of the rooms where you have a fan.
Scientists measure the energy efficiency of air conditioners in two ways. First, they use the energy efficiency ratio (EER), which measures how much energy the unit uses to cool hot air over a certain period. Second, central units are also measured in what is called seasonal energy efficiency ratio (SEER), which also calculates how long it takes the unit to clear the humidity from a room. A window air conditioner, by contrast, is only measured in the EER.
To receive an Energy-Star rating, a central air conditioner must have an EER of at least 12 while a window unit needs to have around a 10 EER. Window units require lower ratings because they technology hasnt caught up yet with the small sizes of window air conditioners. In other words, it is hard to fit highly efficient components into such a small air conditioner unit.
For the consumer, the EER rating gives you an idea of how much energy you will be using and how much running the air conditioner will cost you in electricity bills. Generally speaking, the higher the EER, the lower the electricity bill.
At the end of the day, your decision between buying a window air conditioner and a central air conditioner comes down to the numbers. Window air conditioners are cheaper and easy to install, but cost more in electricity bills. Central air conditioners are expensive and require complicated installation, but cost less in energy bills.
Jane Dabad is the lead writer at The Air Conditioner Guide blog. For more information, check out these helpful guides: Window Air Conditioner Reviews, Should You Buy a Split AC, and Casement Window Air Conditioner Reviews.
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