"Central air conditioners are generally of two types. One is the split central air conditioner and the other is the packaged central air conditioner. In a central air conditioner, the compressor pumps the refrigerant so that it can gather heat and moisture from inside the room and make the temperature inside the buildings comfortable in the process. Central air conditioners are considered more effective than room air conditioners. However, to buy central air conditioners certain factors need to be considered. They are the following: It is mandatory to choose the right sized appliance because an AC that is too small in size will not be able to cool the desired area accordingly and an AC that is too big in size will cycle on and off frequently causing wastage of energy. To determine the right size of a central air conditioner, an HVAC expert needs to be called in who will be able to calculate the cooling requirement of an area exactly. Secondly, one should buy a central air conditioner that has a higher SEER rating. Initially, such an appliance might be expensive but in the long run the investment proves worthwhile. An appliance with higher SEER rating means lesser use of energy which in turn contributes to lower electricity bills."