Compared to central air conditioning, local air conditioning is often considered a second rate form of temperature control. Commonly found in the form of window air conditioners, local air conditioning is designed to cool small areas, whereas central air conditioning uses ductwork to cool an entire building.
The main criticisms of local air conditioning are its lack of energy efficiency, its lack of safety and its unattractive appearance. Concerning energy efficiency, local units tend to use more electricity than central units because their limited air flow makes them work harder to cool an area. Safety wise, local units present the opportunity for burglars to gain window access by removing the units, which can be done in a matter of seconds; however, when the units are placed on the upper floors, safety concerns diminish. As for appearance, window air units aren’t aesthetically pleasing. But if your goal is to stay cool, this point is mute.
The strengths of central energy efficient air conditioning are essentially the antitheses of local air conditioning’s weaknesses: it is energy efficient, safe and it never becomes unsightly. In addition, central units can be purchased with a variety of upgrades, including bacteria filtration, humidifiers, pollen filtration and various other controls. However, the main drawback of a central air system is its costly installation price. A good window unit usually costs less than $200, and if you live in a small house, spending less than $1,000 on window units versus spending at least $12,000 to install central air somewhat negates the value of reduced energy costs.
In most cases, both old and new homes have central air conditioning. But for those that don’t, the debate between buying air conditioners and installing a central air system usually becomes a matter of dollars and cents.