Air conditioners come in different forms—central air conditioners that cool the entire house, portable or window units that cool a single room, and heat pumps.
For those not familiar with the workings of a central air conditioner, it is a refrigerated system that works from a central location to distribute conditioned air throughout the house.
The window- or wall-mounted room air conditioner is designed to cool a small area—typically a single room. If you’re interested in cooling just a couple of rooms—a bedroom and/or living room, for example—one or two portable or window (or wall) air conditioners are an economical way to achieve your goal. You can buy a good one for $300–$500; you’ll find operating it is far less expensive than running a central whole-house system. (For more information, see Types of Room Air Conditioners.)
A central air conditioner borrows a central air handling unit such as a forced-air furnace or heat pump air handler and ductwork for whole-house delivery. The related heat pump is essentially a central air conditioner that can be reversed in winter to heat a house.
Central air-conditioning costs a lot more to install than do several individual room units, but, on the other hand, it is more energy-efficient than a series of portable units. It is also quieter.
A central air conditioner can be a single unit installed next to the house or a split one, with the condenser and compressor outdoors and the evaporator or blower inside on the furnace. The latter is the most economical. With this, the air handler (the furnace blower) delivers cooled air to your rooms through the furnace’s air-duct system. if a house has another form of heating, a separate blower can be used to distribute the cooled air.
