Cooling Your Home

Dependable Tips
and Helpful Information
from your
Better Business Bureau

HOW AIR-CONDITIONING WORKS

TYPES OF AIR-CONDITIONING SYSTEMS

COOLING CAPACITY AND UNITY EFFICIENCY

INSTALLATION AND OPERATING COSTS

FINDING A CONTRACTOR

ENERGY SAVING TIPS

HELPFUL LINKS

Air-conditioning is a very important feature in today's homes. The desire for year-round comfort as well as improved indoor air quality has made air- conditioning a necessity in most climates. Nearly every new home includes air-conditioning as a standard feature, and air-conditioning has been added to most existing homes where its use is feasible. The following information provides the basics about air-conditioning, from understanding related terms to working with a contractor.

Air-conditioning involves more than cooling the air. It includes cooling and heating the air, cleaning the air and controlling the air's moisture level so that people can enjoy maximum comfort indoors. An air-conditioning unit works by removing heat from the air inside a home and releasing that heat into the outdoors. Air-conditioning systems generally consist of six components

• 1. A compressor;
• 2. An outdoor fan;
• 3. A condenser coil (hot);
• 4. An indoor fan;
• 5. An evaporator coil (cold);
• 6. A chemical refrigerant.

As the indoor fan circulates the warm indoor air across the evaporator coil, the refrigerant absorbs heat from that indoor air. The refrigerant is then pumped by the compressor to the condensing coil. The outdoor fan blows outside air across the hot condensing coil, and the heat is transferred from the refrigerant to the outside air. As it enters the indoor coil, the refrigerant is quite cool, and that cooling is transferred into the home by the indoor fan.

Although there are many types of air-conditioning systems, most are a variation of either the "split system" or the "single package." Most single family homes have a split system. In a split system, the indoor fan/evaporator coil are located separately from the outdoor fan/condenser coil/compressor. A single package system combines all of the components described above together in one unit. This unit is typically located on the roof or on the ground adjacent to the home. Both of these systems reduce indoor noise by locating the compressor, con-denser and outdoor fan outside the home. The single package reduces indoor noise levels even more because the "indoor" supply and return fan is also located outside. However, it is usually more difficult to make ductwork connections with a single package unit.

If a home does not have central air-conditioning, either system may be used. In some cases, it may be necessary to add a ductwork system to distribute the cooled air throughout the home. If a home does have central warm air heating with ductwork sized for moving cooled air, a split system may be used.

When selecting a central air-conditioner or heat pump, the cooling capacity and efficiency of the system are important points to consider.

Cooling Capacity: The cooling capacity of air-conditioners (and heat pumps) is measured in terms of British thermal units per hour (Btuh's). Each 12,000 BTUH of air-conditioning equals one ton. For example, 36,000 BTUH is three tons of air-conditioning. When purchasing an air-conditioning system for your home, it is important to make sure that it is properly sized for the home. A system that is too small may not produce enough cooled air to make your home comfortable. An over-sized unit may perform inefficiently, often causing a cold, clammy feeling. An air-conditioning contractor should be consulted to calculate the proper size system needed for your home.

Efficiency: In addition to adequate cooling capacity, your unit should be efficient. Although the initial cost will probably be higher, a more efficient unit uses less energy and should save significant money over the life of the unit. For example, a new central air-conditioner's annual operating costs may be half of what an older model costs to run. To evaluate unit efficiency, you must know a few terms. The energy efficiency for an air-conditioner and the cooling side of a heat pump are shown by the Seasonal Energy Efficiency Ratio (SEER). The SEER indicates how much cooling you receive from each watt of electricity you use on a seasonal basis. The higher a unit’s SEER, the higher its efficiency. Using the SEER, you may easily compare the efficiency of different units. For example, if Unit A's SEER is 10 and Unit B's SEER is 5, Unit A is twice as efficient as Unit B and will cost approximately half as much to operate. Manufacturers are required by law to publish the energy efficiency rating and estimated annual operating costs of their residential air-conditioning systems. If you are buying an air-conditioning system be sure to look for the SEER.

Each air-conditioning system should be designed for the particular home where it is to be installed. A contractor should survey your home and calculate its cooling load before preparing a quotation. Obviously, the most economical time to install air- conditioning is when a home is being constructed. Adding cooling to an existing home incurs additional costs due to modified or additional ductwork, the addition of ceiling or wall insulation, and/or the modification or enlargement of the electrical system due to the additional energy load of an air-conditioning system. Ductless air-conditioners are available that operate like split systems but can be used to cool one or more rooms without ductwork.

Operating costs of air-conditioning systems vary depending upon several factors:

• Size and efficiency of the unit;
• Local cost of electricity;
• Climate in your area;
• Amount of glass area and shading;
• Adequacy of insulation and weather- stripping;
• Direction home faces relative to the sun; and
• Your family’s specific usage (door usage, cooking, clothes drying, etc.)

Ask friends and neighbors to recommend a contractor who has performed a good job for them. The classified section of the newspaper and the Yellow Pages are additional sources to check. You can request a Reliability Report about a contractor from your Better Business Bureau (www.bbb.org/bureaus).

Evaluating Bids: To get the best price, you will want to ask two or three contractors to inspect your home and give you a written cost estimate describing the system to be installed.

• In Writing: Bids for extensive repair or replacement of air-conditioning systems should be submitted in writing. Estimates should always include a full description of the services to be provided. If the air-conditioning system is to be replaced, the estimate should include a description of any extra work to be performed, such as increased electrical wiring, etc.
• Size Calculation: Have the contractor calculate the size of the air-conditioning unit required. Check sizes proposed by the contractors. Compare more than cost when examining bids. Remember it is difficult to put a price on your comfort. Be sure that you obtain the maximum in both comfort and value.
• Warranties: Check the warranties offered: what does it cover, for how long and who will honor it? Always keep a copy for your records.
• One Year Free Service: The contactor you choose should provide at least one year of free service labor should any malfunction occur.
• Maintenance: Check the owner's manual and contractor's recommendations regarding routine maintenance.
• Know Your Contract: Read the contract thoroughly and understand it before signing. Be sure to keep a copy.

There are a number of things you can do to help keep your central cooling system operating at maximum efficiency:

• Keep Heat Out: Weather strip and insulate your home properly; use drapes, blinds and curtains, and plant trees and shrubs to shield out the heat and sun.
• Adjust Thermostat: Set the thermostat to a comfortable temperature and leave it there. Air conditioners are sized to operate during the hot weather. A properly sized air-conditioning system will also remove moisture in the summer to keep your home comfortable. A modern set-back thermostat can be used to match your family’s life-style. This thermostat automatically sets itself at higher settings when you are not in your home.
• Protect Outside Unit: Keep any outside units clear of shrubbery and grass so that the flow of air over the condensing coil is not reduced.
• Housekeeping: If possible, schedule cooking and clothes drying during the early morning and late afternoon hours rather than during the hottest hours of the day.
• Keep ’em Shut: Make sure all windows and doors are closed when your cooling system is on.
• Fresh Filters: Your system should include a good air filtering unit. These vary in types from simple "throwaway" filters, to pleated Media Filters, to Electronic Air Cleaning Units. Have your contractor show you the various options available. Replace or clean the air filter as needed, generally every 30 days during heavy cooling periods.
• Annual Maintenance: Have your air-conditioning unit serviced on an annual basis by a reputable contractor.

To learn more about cooling your home, contact the following: YOUR LOCAL BETTER BUSINESS BUREAU Web site: www.bbb.org/bureaus AIR-CONDITIONING & REFRIGERATION INSTITUTE (ARI) at 703.524.8800, Web site: http://www.ari.org/ FEDERAL TRADE COMMISSION at 877.FTC.HELP (877.382.4357), Web site: http://www.ftc.org/ U.S. DEPARTMENT OF ENERGY Web site: http://www.bbb.org/ To locate an air-conditioning contractor, see: AIR-CONDITIONING CONTRACTORS OF AMERICA (ACCA) at 202.483.9370, Web site: http://www.acca.org/ SHEET METAL & AIR-CONDITIONING CONTRACTORS NATIONAL ASSOCIATION Web site: http://www.ftc.org/ * If you find any of the web sites listed above to be inactive, please contact the respective organization. Also, be aware that the above phone numbers may be subject to change without notice.

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