It is important to choose the right sized air conditioner for a comfortable cooling. If you install a wrong sized air conditioner then it will fail to maintain a comfortable level of temperature. Improper sizing will also lead to an increase in energy bill hence you will end up paying more than what you otherwise will have to. It will also cause the air conditioner to break down due to over working of the unit. To get the right sized cooling unit you need to consult a HVAC contractor. It is possible to do it yourself but you will have to do so by some online research in order to calculate it correctly and effectively. Following a few methods explained here can help you determine the right size. First you will have to determine the ideal temperature in which you and your family will feel comfortable. Once you have determined the temperature level up to which you want your air conditioner to cool calculate the difference between the actual temperature inside your house and the temperature that you want your air conditioner to cool up to. Based on these calculations you will be able to determine the load of the air conditioner that you are going to install.
Manual J is a method that is used by the professionals to calculate the right load of an air conditioner. Though it is complicated searching online will give you an idea and help you determine the right size unit required for cooling your house. The two types of Manual J calculation methods are whole house load calculation and room by room load calculation.