Window Air Conditioners: Cool Small Spaces Effectively and Economically

When only a single room needs to be cooled rather than an entire home or business, a window air conditioner is a more economical choice than central air conditioning. The initial costs are less expensive and they cost less to operate over time. These appliances sit in a window so that warm air can be exhausted to the outside. They do not need to be permanently installed, so during the winter they can be stored to prevent drafts. Some window air conditioners can be built into the wall for a more permanent installation as well.

The important thing to take note of when choosing a window air conditioner is the cooling capacity. Cooling capacity is measured in BTUs (British Thermal Units) per hour. If you purchase an ac without enough BTUs, it will run continuously without cooling the room effectively. If the window ac has too many BTUs, the room will be cooled too quickly and the unit won’t remove as much humidity from the air as it should. It will turn off and on repeatedly and the room will feel damp, clammy and uncomfortable. Also, if the unit has a cooling capacity that is too large it will cost more and use more energy. A properly sized unit removes humidity effectively as it cools.

To purchase a window air conditioner that has the correct cooling capacity you should follow a few simple steps. First you’ll need to measure the space that needs to be cooled. You can estimate the square footage that needs to be cooled by multiplying the length of the room by the width. Here is a chart that presents the recommended BTUs for the amount of space to be cooled:

Square Footage	Amount of BTUs Needed
100 to 150	5,000
150 to 250	6,000
250 to 300	7,000
300 to 350	8,000
350 to 400	9,000
400 to 450	10,000
450 to 550	12,000
550 to 700	14,000
700 to 1,000	18,000
1,000 to 1,400	24,000

Some helpful hints for choosing the correct cooling capacity include:

-Reduce BTU capacity by 10 % if the room is heavily shaded.

-Increase the BTU capacity by 10% if the room is very sunny.

-Add 600 BTUs per person if more than 2 people regularly occupy the room.

-Increase the capacity by 4,000 BTUs if the window air conditioner is for a kitchen.

Another important factor to include in your window ac decision is the EER (Energy Efficiency Ratio). This figure approximates the unit’s operating cost as compared to similar models. The higher the value of the EER, the less it will cost to operate. If possible, try to choose an Energy Star rated window ac. These units have high efficiency compressors, fan motors and heat transfer surfaces. The amount of energy required to compress the refrigerant is reduced. They exceed the minimum federal standards for energy consumption by at least 15%.

Some important features to look out for are an energy saving feature, 3 speed fan controls, digital thermostats, an adjustable timer and an easy slide-out filter. The energy saving feature cycles the compressor off and on so that it doesn’t operate continuously and operating costs are reduced. 3 speed fan controls allow the adjustment of the amount of cool air (and noise) the window ac produces. Digital thermostats keep your unit precise and easy to use. A timer allows the window air conditioner to come on when you desire so it isn’t controlled by the temperature of the room only. Finally, most air conditioners have filters that need to be cleaned periodically, so choose one with a filter that easily slides out. Keeping the filter clean save money and energy.