A central air conditioner is more than just the largest appliance in a home—it’s part of a carefully designed system that also incorporates a thermostat and an array of ducts that deliver and circulate cooled air throughout the structure. In most cases, a central air-conditioning system is a more energy-efficient choice for regularly cooling a home than using room air conditioners in three or four different rooms.
However, there’s no getting around the fact that a central air conditioner can be fairly expensive to purchase—and that it must be installed by a qualified heating and cooling contractor. If your home doesn’t have central air-conditioning—but does have a network of ducts for a forced-air furnace—you likely can use the same ducts for cooling, as long as they’re the proper size and free of leaks and obstructions. On the other hand, if your home is heated by a boiler or electric baseboard units, you’ll need to add a duct system, which can be both difficult and expensive—especially in a multi-level home, where you might have to sacrifice closet space or build “chases” along walls or in corners to hold the ducts.