How to Pick Central AC Units

Look into the difference between a split-system central AC and a packaged central AC unit. A split-system is housed outside in a metal container, and if you do not have a central AC unit already installed that you're replacing, a split-system is a good choice. A packaged central AC unit is housed in a cabinet on your roof or near your foundation and is generally installed in combination with a gas furnace or hearing coils, which means you no longer need a separate furnace.

Check to see if the central AC units you're picking from are energy efficient. The presence of an Energy Star label will tell you that the air conditioner is approximately 14 percent more efficient than other AC units. Energy Star is a government program that ensures products like central AC units meet set guidelines for energy efficiency.

Find out the seasonal energy efficiency ratio, or SEER, for the central AC units you're comparing. Thirteen is a standard SEER rating, and anything above that is more efficient than government standards require.

Get your central AC unit sized for your home. This should be done by a central AC installation professional. You can judge the square footage yourself, but other matters to consider include your insulation, ventilation, climate and humidity level where you live. A professional uses specific methods, programs and equations to determine the proper size for your central AC unit.

Pay attention to any special features that come with the unit you're considering, such as a fan-only switch, quiet operation, a filter check indicator light or an automatic-delay fan switch.