Room air conditioners put the cooling you need directly where you need it. They are a great solution for people who cannot install a central air conditioner in their building because it is not feasible or too expensive. The technology of room air conditioners has come a long way. They are up to thirty percent more energy efficient than they were just one short decade ago. They also have longer warranties so worrying about maintenance and repairs is a thing of the past.

It is a great idea to buy room air conditioners early. Buying them before summer starts certainly saves you money. Companies can get top dollar for these units in the summer, but during the off season they often have sales.

An important thing to consider when purchasing a room air conditioner is matching the unit to the room it is going to be cooling. If the cooler is too small, it won't cool the space. If it is too large, it will cool the space too quickly and the built-in thermostat will shut the unit down before the humidity in the room is lowered. This means the room will feel damp and clammy.

Room air conditioners are sized according to BTUs per hour, also known as the cooling capacity. This number can be found on the packaging of the unit or in literature about the product. BTUs of room air conditioners typically range from 5,000 to 25,000. To figure out which room air conditioner is right for them, most people compare the square footage of the room to BTU capacity. The Association of Home Appliance Manufacturers (AHAM), a Chicago based industry group has a more complex formula. It includes window area, sun exposure, insulation levels, how the room is used and other variables. For a more complete way to find the right amount of BTUs for you, their formula may be helpful.

Be sure to note that for 115V circuits typical of bedrooms and living rooms, you'll have to stay below 15,000 BTUs. Anything above that will require a 230V circuit. Also, if you are trying to cool an oddly shaped space with corners, it is better to have two smaller room air conditioners instead of one large one. Having two units will prevent cold spots in front of the air conditioner and warm spots around the corners. Mainly, you should try to keep cold air from pooling on the floor.

A very important consideration is Energy Efficiency Ratio (EER). This value is the cooling capacity divided by the electrical power required to run the unit. The higher this number is the better. The federal government requires manufacturers to list the energy rating on the unit. An EER of nine or ten is typical on an 115V room air conditioner. If a unit has an EER of ten it is considered extremely energy efficient. You will pay more up front for energy efficiency as well as for a high cooling capacity but you make up the increase in cost with the energy savings.

One last important consideration is the amount of control features. To fine tune the output of your room air conditioner for maximum comfort, look for units with multispeed fans and adjustable thermostats. If you are operating a room air conditioner in a bedroom, you can cool the space and then switch to a lower setting for quieter operation. Digital controls are even a higher step up, offering precise temperature control and sometimes even a timer for turning power on or off on a preset schedule. Also consider where the controls are located and whether it will be comfortable for you to reach them.