There are mainly two types of air conditioning systems – central and room.

Here we will focus more on room air conditioners as they are widely used in homes worldwide while central air conditioners are most commonly used in commercial buildings and places.

Room air conditioners are small cooling systems and can be mounted in a window, through a wall or in a portable cabinet on a floor near a window. It cools the air in the room and keeps you comfortable on a hot day. There are reverse intake air conditioners that also work as heaters on a cool day to keep the room warm.

Room air conditioners are low cost and comforting low-maintenance cooling systems that can serve the cooling needs of a room for many years at a relatively low price. When it comes to buying a room air conditioners, knowing what, when and how to buy can help you save some money and get the best deal.

Price of a room air conditioner depends on several factors such as – features, warranty, after-sales-support etc.

The time of buying an air conditioner is also very important. Shopping for an air conditioner early or late in your local summer season means you can find reduced prices on units by as much as 20 - 25 %.

Let us know discuss and understand some of the basic and important points to keep in mind while buying a room air conditioner.

Here are some of the basic and important points to keep in mind while buying a room air conditioner (AC):

Area of the room:  guidelines : Room air conditioners are rated in Btu capacity. For a small room if an area 100 to 300 sq. feet you should select an air conditioner of 5,000 to 6,000 Btu/hr. For a medium-size room with an area of 300 to 600 sq. feet, choose a unit of 8,000 to 9,000 Btu/hr. For larger rooms of an area of 600 to 1,000 sq. feet choose a unit of 10,000 to 15,000 Btu/hr.

If the insulation in your home is too low or the air conditioner is installed in a south-facing window which is normally too hot, you need to choose a unit with higher Btu. Also keep in mind that if the room you are cooling has a taller ceiling then you will need about 10 % more Btu to cool the air in the room adequately. If possible, avoid installing the cooling unit in a south-facing window that gets lots of sunlight as it reduces the unit's efficiency. Keep in mind that if you buy an air conditioner with a higher Btu rating than needed, it will cycle on and off too quickly which means it will use more energy and will cost more to operate and remove less humidity from the air. Alternatively, if you use an air conditioner with a low Btu to cool a too-large room, it will run continuously and cost more to operate. Do this homework and research before you buy your air conditioner.

Best place to install an air conditioner: Normally a room air conditioner is installed in a window. This is not a good practice since the windows need to be opened regularly. This affects the performance of the AC. The best option is to install the air conditioner permanently through the wall to make a better seal firm support. Other option includes buying a portable air conditioner. Work on this before buying and installing your air conditioner.

Multipurpose air conditioners:  There are multipurpose air conditioners. Some of them also act as dehumidifiers and some play the role of room heaters. Depending on where you live, humidity and climate, you should wisely choose your air conditioner to meet all your requirements and comfort. For areas with arid summer climates, an air conditioner with a built-in humidifier can add moisture to the air to make the room more comfortable. An air conditioner with built-in dehumidifier can remove moisture from the air. Some AC models serve as heaters to warm the air as needed on cool days. Work on this before buying an air conditioner so that you get the best deal.

 Controls of Air Conditioner:  Before buying an air conditioner, you need to look at its’ features and controls. Technological advancement has made  today's air conditioners are much smarter. You can set a unit for say 72 degrees and it will maintain the air temperature with little tolerance of say ± 1 Degree. For your convenience and comfort, many room air conditioners now wireless remote controls that let you change settings and direction of the airflow. Many units have timers to program the unit to start or shut off, so you can set the AC to turn on just before you get home or turn off when you go to sleep. An important feature of most room air conditioners is the filtration system. Almost all units have a foam filter that can be cleaned. Some use electronic air filtration to remove dust and pollens from the air. Make sure that the filtration system is adequate and easy to maintain.

Budget: How much can you invest in cooling a room is an important factor. If your  room only gets hot forfew days in the summer, you may want to invest in a less expensive model. If the cooling season is long and the room is too populated, you should invest in a more expensive and more powerful unit. Price of room air conditioners range from $100 to $1,500 with most common of them are available in the range of $250-$600. Lower priced models often have manual controls and higher priced units may include a dehumidifier or a heater. For about $350, you'll get an energy-efficient 8,000 to 10,000 Btu air conditioner with adequate features and a remote control, which is just right for most applications and climate.

When buying an air conditioner, make sure that it is quiet. For e.g. If you want to install a room air conditioner in your bedroom, you will definitely like the AC to be quiet so that you do not get disturbed while sleeping.

Make note of the warranties offered. Many manufacturers offer a 1-year full warranty, while some offer a 5-year limited warrant. Many others offer 5-year limited warranty on parts such as the condenser etc. Few others offer onsite warranty so that you don’t have to visit the service center to get your AC repaired. Before you buy your air conditioner, read all these offers and make a wise selection.