Let's face it, central air conditioning has become an integral part of the American homeowner's lifestyle.

A recent study shows that seven out of every ten new homes built today include central air conditioning as a standard feature.

Thousands of other homeowners are adding central air to their existing homes.

Yet, how many owners or prospective owners of central air conditioners know how the system works?

According to a recent study by the Trane Home Comfort Institute, not that many.

To help you understand how this integral part of your home operates, the Trane Home Comfort Institute offers this simplified explanation:

A central air conditioning system essentially consists of two parts: the coil, which extracts unwanted heat and humidity from your home, and the condenser, which discharges the unwanted heat to the outdoors.

Most residential air conditioners are split systems, meaning that the coil is located indoors and the condenser, outdoors. When the coil and the condenser are both located outdoors in the same unit, the system is called a packaged system.

In a split system, two copper tubes called refrigerant lines connect the indoor coil and the outdoor condenser. The smaller of the lines is called the liquid line; the larger, the suction line.

The lines are filled with a chemical refrigerant which has a boiling point low enough that it evaporates at relatively low temperatures and takes heat and moisture out of the air as it passes through the coil. The refrigerant travels in a closed loop between the coil and the condenser.

The loop begins as the liquid refrigerant passes through the coil, which is a network of tubes located on top of the furnace.

As the refrigerant travels through the coil, it evaporates from a liquid to a vapor, absorbing heat by cooling the air passing around the coil. The furnace blower distributes the cooled air through ducts into the interior of the house.

Meanwhile, the vaporized refrigerant moves through the suction lines to a compressor in the outdoor unit. The compressor compacts the vapor and then moves the hot refrigerant gas under high pressure through the condenser, which is a network of tubes exposed to outdoor air. As the refrigerant travels through these tubes, it cools and turns back into a liquid. The heat released during this condensation process is dispersed into the outdoor air by a fan.

The refrigerant then flows through the liquid lines from the condenser back to the coil inside the house and the cycle begins again.

The compressor is considered "the heart of the system" because it is the pump that circulates the refrigerant through the loop. Because of its importance, experts at the Trane Home Comfort Institute recommend that you look carefully at the compressor's reputation and warranty when selecting a system.

They also recommend checking the SEER or Seasonal Energy Efficiency Rating, which is an indication of a unit's efficiency. The higher the SEER, the higher the efficiency. The higher the efficiency, the less electricity needed to cool your home.

In addition, it's important to note that an outdoor condenser can be combined with dozens of different indoor coils. To obtain the rated efficiency, make sure the capacity and SEER of the indoor unit matches that of the outdoor unit.

Finally, you want your new central air conditioning system to operate for a long time, so compare the reliability and durability features of the equipment you select to get the most for your money.