The most commonly used air conditioners are window air conditioners. This is due mostly to the fact that they are the cheapest alternative when it comes to cooling our homes. But there are other reasons also. For example they install in a window out of the way. Install it and forget it. These units are also available with electric heat options.Window air conditioners were once so noisy that they were nicknamed window bangers. This term was very accurate and well deserved. However today’s window air conditioners are very different from the ones many of us learned to hate. Window units of today are very quiet and their efficiency has improved a lot also. In fact these units are so quiet that you can hardly even hear them operating.Window air conditioners have the same components as a central air conditioner but they are all installed in small cabinet. The biggest and most important difference is that they don’t have to cooling capacity of central units. But they also don’t cost as much to operate either. If you only want to cool one or two rooms then window air conditioners are a perfect choice. However if you want to cool your entire home a central air conditioner is the best alternative.Another huge improvement in window air conditioners is in their appearance. Older models did not blend in very well with their surroundings. They were usually some shade of brown and looked like there was a box in your window. Window air conditioners today are much less obtrusive and look less like boxes. Corners are rounded and colors are much lighter. This gives them a much sleeker look.As with most things, once they have been around for awhile cost become more reasonable and less of an obstacle. A window air conditioner can be purchase for less than two hundred dollars and often not much more than one hundred dollars. Of course this is for smaller units. Costs go up as the cooling capacity of the unit increases.When purchasing a window air conditioner it is very important to purchase one with the proper cooling capacity. An air conditioner that is not properly sized will not work as efficiently as one that is sized properly. This is one of the most common mistakes made when selecting air conditioners. Use an air conditioner size calculator to select the proper sized unit for the room you want to cool.Undersized air conditioners will run continuously and not cool the space adequately and an oversized unit will cycle on and off too often. This increases equipment wear and can actually cause fuses to fail. An additional benefit of a properly sized air conditioner is humidity control. While these units are operating, moisture condenses on the evaporator coil just like a dehumidifier.Probably the most common problem with window air conditioners is that they sometimes develop rattling noises due to vibration. This is not a serious problem and can be rectified very easily by checking to make sure all screws are tight and check that the unit is mounted correctly in the window and not twisted or stressed.