Basic Operations:
Air conditioning includes both the cooling and heating of air. It also cleans the air and controls the moisture level. An air conditioner is able to cool a building because it removes heat from indoor and transfers it outdoors. A chemical refrigerant in the system absorbs the unwanted heat and pumps it through a system of piping to the outside coil. The fan, located in the outside unit, blows outside air over the hot coil, transferring heat from the refrigerant to the outdoor air.The compressor is the "heart" of the system. The compressor acts as the pump, the refrigerant flows through the system. It draws in a low-pressure, low-temperature, refrigerant in a gaseous state and by compressing this gas, raise the pressure and temperature of the refrigerant. This high-pressure, high temperature gas then flows to the condenser coil.The condenser coil is a series of piping with a fan that draws outside air across the coil. As the refrigerant passes through the condenser coil and the cooler outside air passes across the coil, the air absorbs heat from the refrigerant which causes the refrigerant to condense from a gas to a liquid state. The high pressure, high-temperature liquid then reaches the expansion valve.The expansion valve is the "brain" of the system. By sensing the temperature of the evaporator, or cooling coil, it allows liquid to pass through a very small orifice, which causes the refrigerant to expand to a low-pressure, low-temperature gas. This "cold" refrigerant flows to the evaporator.The evaporator coil is a series of piping connected to a air handler that blows indoor air across it, causing the coil to absorb heat from the air. The cooled air is then delivered to the house through ducting. The refrigerant then flows back to the compressor where the cycle starts over again. Heating and cooling your home uses more energy and drains more energy dollars than any other system in your home. No matter what kind of heating, ventilation, and air conditioning system you have in your house, you can save money and increase comfort by properly maintaining and upgrading your equipment. By combining proper equipment maintenance and upgrades with appropriate insulation, weatherization and thermostat settings, you can cut your energy bills and your pollution output in half.

Saving money on your energy bills will depend on four major factors:
• Energy efficiency of your system
• Managing system operation
• Simple system maintenance

Save Money:
One of the easiest ways to save money on your energy bills is to buy a high efficiency heating and cooling system. Keep in mind that:
Even the lowest efficiency systems currently allowed by the U.S. Government will almost always cost less to operate than a system that was installed ten years ago.
Most manufacturers offer higher efficiency models which will add to your savings on monthly utility bills.
Typically, higher efficiency systems will cost more initially, so it's important to look for the right balance between cost and long-term savings.

Managing System Operation: No matter how efficient your system is, managing the operating system can affect your heating and cooling costs. Naturally, you want to feel comfortable when you're home. But do you really need all that comfort when you're not home? Do you need all of that comfort while everybody's in bed, sleeping? By remembering to "set back" the temperature on your system's thermostat during times when you don't really need as much comfort, you can save significantly on your monthly utility bill. Programmable zoning systems can provide even greater efficiency and comfort by dividing the home into comfort "zones" and providing differing temperatures for each zone.

Simple System Maintenance: One of the keys to energy savings is keeping your system operations at its best.

Two simple ways you can help maintain your system are:
• change fan coil filter frequently
• clean indoor and outdoor coils

Age and Condition of Your Home:
For a variety of reasons, newer homes are more energy efficient than older ones. They are built to keep conditioned air inside so you are not paying to heat and cool air that easily finds its way out of your home. As a home gets older, settling will cause some of that airtight construction to loosen up.

Regardless of your home's age, you can do some simple maintenance to make sure that will help keep the conditioned air inside, where it belongs.
• Be sure your home is adequately insulated. Adding insulation to attic areas is usually pretty easy. Other areas, such as outside walls, provide a more challenging project if extra insulation is needed.
• Check the seals around windows, doors, electrical outlets or any other potential sources for escaping air. Seal these areas using a good quality caulk, and be sure to re examine your handiwork every few years.
• Inside your home, weather stripping around moving parts of windows and doors can help seal off potential areas of leakage or drafts.
• Storm doors and windows can provide additional energy savings by preventing air loss and by creating an insulating layer of air.