Energy Efficient Air Conditioning
Written by Elizabeth Wood
Editor In Chief, United Home Improvement

In order to get the most out of your air conditioning system, it is important to understand the different designs, components, and operating principles. Paying close attention to the proper sizing, selection, installation, maintenance, and correct use are keys to lowing your overall costs.

How it Works:

Air conditioners and refrigerators work in very similar ways. Air conditioners consist of chemicals that convert from a gas to a liquid and back again. It uses these chemicals to transfer heat from the air inside of a home to the outside air. The system is divided into three main parts which include a compressor, a condenser and an evaporator. The condenser is an outdoor coil and the evaporator is an indoor coil. The compressor is a pump that moves a heat transfer fluid (or refrigerant) between the evaporator and the condenser. The compressor pushes this fluid through the circuit of tubing and fins in the coils. It is when the fluid evaporates in the indoor evaporator coil, that hot air is removed and the home becomes cooler.

Types of Air Conditioners:

• Room Air Conditioners: Used to provide cooling only where needed. They cool off individual rooms, as opposed to the entire house. Generally, they are cheaper than central air systems; however, their efficiency is typically lower. Small systems can work off any 115-volt household circuit. Larger models will need a dedicated 230-volt circuit.

• Split-System Central Air Conditioners: Central cooling units used in homes, where extending or installing distribution ductwork is not feasible. Mini-split systems are ductless, individual cooling units that require a conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain to link an outdoor compressor/condenser and indoor units.

• Packaged Central Air Conditioners: Used to cool an entire home. Supply ducts and registers carry cooled air from the air conditioner to all areas of the home. As the air begins to get warmer, it then flows back to the central air conditioner through return ducts and registers and the process is repeated. A central air conditioner is either a split-system unit or a packaged unit.

Proper Sizing

British Thermal Units (BTU's) are used to rate the size of air conditioners. A different rate is given depending on the number of BTU's of heat that can be given off per hour. An air conditioner's efficiency, performance, durability, and initial cost rely greatly on not only its size (BTU rating), but also on the below factors.

• The amount of heat the occupants and appliances in your home generate.
• The amount of shade that is on your home's windows, walls, and roof.
• The amount of insulation in your home's ceiling and walls.
• The size of your home and how many windows it has.
• The amount of air leaking into your home from the outside.

Make sure that when installing an air conditioning system, you know that bigger is not always a better option. The size of your home and proper installation play a bigger role on the success of your system. Consult with a professional installer about the air conditioning system that is right for your house.

Air Conditioner Efficiency

Investing in an energy efficient air conditioner is highly recommended. You will find a price tag attached to such models, but the money you will save in the long run will not only cover the initial cost, but it will save you more. Each air conditioner has an energy-efficiency rating. Room air conditioner are rated using the Energy Efficiency Ratio, or EER. Central air conditioners are rated using the Seasonal Energy Efficiency Ratio, or SEER. These ratings can be found on the Energy Guide Label. Certain manufacturers will also use the EnergyStar® labeling program.

Maintenance

You will need to hire a qualified service technician when your air conditioning system requires more than the usual maintenance. You want to make sure that you are not getting ripped off during these service visits. To ensure that you are getting proper service, make sure that your technician covers the following check ups:

• Checks the refrigerant for the proper amount. A low level indicates a leak, to be found and repaired before adding more Freon.
• Checks for leaks.
• Check for and seal duct leakage in central systems.
• Check the accuracy of the thermostat.
• Clean evaporator and condenser coils, as needed.
• Check filters and condenser.
• Check all electrical components and controls.
• Oil motors as needed.

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