Central Air Conditioning

A traditional home comfort system has two parts: an indoor unit, such as a furnace or air handler, and an outdoor unit. An air conditioner is the outdoor unit that cools air and sends it to the indoor unit for circulation through your home. Indoor and outdoor units are designed to work together. When the air conditioner is properly matched with a furnace or air handler, you get maximum efficiency and longer system life. Air conditioning and cooling efficiency is measured using a Seasonal Energy Efficiency Ratio (SEER). A higher SEER means higher energy efficiency. The latest standard for SEER is 13 (beginning January 2006).

A split-system air conditioner or central air conditioner splits the hot side from the cold side of the system.  The cold side, consisting of the expansion valve and the cold coil, is generally placed into a furnace or some other air handler. The air handler blows air through the coil and routes the air throughout the building using a series of ducts. The hot side, known as the condensing unit, lives outside the building.

The unit consists of a long, spiral coil shaped like a cylinder. Inside the coil is a fan, to blow air through the coil, along with a weather-resistant compressor and some control logic. This approach has evolved over the years because of its low-cost, and also because it normally results in reduced noise inside the house (at the expense of increased noise outside the house).