To increase energy savings, newer window air conditioners have an energy saver setting that turns the unit off and on while cooling the room. This saves you money on your electric bill. It works on the theory that the unit turns on the unit compressor and fan to cool the room unit cool. At this point, older units would have the unit compressor shut off, while continuing to run the blower fan, circulating the air. This still maintains the use of electricity throughout the entire time the widow air conditioner is used. That's where the difference begins with the newer style window air conditioners.
You see, at this point, when the room is cooled to the desired temperature, the newer style turns itself off completely as not to use any electricity, other than monitoring temperature. The unit then senses temperature change unit the room begins to once again heat up, at which point the unit is turned back on and it continues its cooling stage again.
Along with the energy-saving window air conditioner, I often use my ceiling fan to circulate the air, usually on the low setting. This keeps the air from stagnating and provides a cool breeze via the work of the window air conditioner. The ceiling fan is quite efficient, much more than that of the blower fan within the window air conditioner, and the ceiling fan does a great job of mixing the room air to provide a nice uniform temperature in the room.
For me, this style window air conditioner works well and saves me money on my electrical bill. I actually have a small 6,000 BTU window air conditioner upstairs in a window, which cools a 900 square foot room by night and is left on with the door open to maintain the entire upstairs and main level of the house temperature by day. You'll be as surprised as I was at how well this works. I do have a central air conditioner that comes on at some point during the day when temperatures climb. However, this may not occur until the hottest part of the day and for minimal hours a day, which again translates into saving me money on my electrical bill. After all, why continually have a fan running all day if you don't need to? This type window air conditioner just makes good sense and is easily set to energy saving mode with the push of a button. Oh yes, they do have the option to run it the old fashioned way, but the money this unit saves in a season will likely pay for the unit the first year. Another nice feature is a remote control that can be operated anywhere in the room. This saves you from getting up in the middle of the night, if you want to adjust the cooling setting or turn the unit on or off.
All you have to do now is determine which size air conditioner you need. Calculating the needed BTU air conditioner is easy if you can do a little math. If you still have an energy gulping window air conditioner of the past, you might want to consider the energy saving models that will pay to make a change.