Deciding when to purchase a new system
If your cooling system is less than 10 years old, it should still have some life left in it. You can expect as many as 10 to 15 years of service from properly installed and maintained cooling equipment. To help make this long service life a reality, it is a good idea to have your cooling system inspected and adjusted on an annual basis. If your system is over 10 years old, then you should definitely place it on an annual maintenance program. Good preventive maintenance will ensure your system runs safely and efficiently for a long time.

If you are the owner of an older air conditioning system, you may be wondering if it will last another year. You are concerned that it may stop working in the middle of the summer, leaving you and your home hot and soggy. If this is the case, it's probably time to call on an expert to consider replacement or repair. Home air conditioning systems can be expected to last for 15 years or more. Good maintenance practices will, of course, provide an even longer service life. Deciding when to replace an old cooling system is not easy.

Unless your present system is old and in very poor working condition, it may be hard to justify a new high-efficiency system on energy savings alone. If your system doesn't seem to be working as well as it used to, you should have a service person look at it to determine the likely cause of the problem. If there is a significant problem, simply comparing the price to repair the system with the cost of replacement will give you a good idea of what you should do. Keep in mind, however, that, due to improvements in efficiency, a new system will have the added benefit of reducing your operating cost. If your system is over 10 years old, you may want to consider a new unit. Especially if you have a large home with a high cooling load, the annual dollar savings from installing a new system may pay for itself in a short time.

Choosing a system type
Central air conditioning is becoming increasingly popular in American homes. Over 47% of all homes have central cooling and an additional 26% have room air conditioning units. Some homes use heat pumps for central air conditioning as well as heating. The table below shows the prevalence of all of the common types of cooling systems found in the United States. Air conditioning is more popular in the South and West where almost 70% of homes have central cooling systems. In the Northeast, 40% of homes use room air conditioners while only 22% have central cooling systems.

Central Systems
As you can see there are couple of options with regard to central air conditioning types. You can choose to install a cooling-only system or a heat pump, which will provide heating and cooling. If you currently have a heat pump, then you will probably want to stick with a heat pump. Otherwise, you will have to add some type of heating to your system.

Homeowners in the Northeast sometimes switch from a heat pump to a gas or oil furnace with central air conditioning. The reason behind this is that air source heat pumps do not perform well in extremely cold conditions. Another option in this situation is to stick with the heat pump and add gas or oil back-up heat through a hydro-air type system. This is a complicated change, however, and should be discussed with a heating and cooling professional. Heat pumps are very popular in the South, where they comprise 66% of the central air conditioning systems. If you live in a home in this area with electric heat and central cooling, you should consider switching to a heat pump for heating and cooling. By doing so, you will save a good percentage of your heating bill.

Ductless Split System
In the past, for houses where it was impractical to install central air conditioning, the homeowner was left with the option of placing a room air conditioner either in a window or wall. Now there is another alternative for cooling your home without the expense of installing a central A/C unit and ductwork. The Ductless Split System is similar to the central air conditioning system only without the ductwork. Both systems are based on an indoor unit—with cooling coil and blower, and an outdoor unit—with the condenser and compressor. The indoor unit and outdoor unit are connected by two small copper pipes which carry refrigerant back and forth. Installation of a Single Zone ductless split system will require the services of a professional heating and cooling technician. The indoor unit typically mounts on the wall, but floor models are also available. These units have built in thermostats and usually come with a remote control for turning the unit on and changing the set point. A Single Zone system has one indoor unit, but it can still serve more than one contiguous room in a fairly open floor plan. Two and three zone systems are also available.

Choosing a contractor
Once you have a pretty good idea what type of system you want to install, it is probably time to talk to a contractor. Replacing a cooling system or heat pump is not a do-it-yourself project for most people. When choosing a contractor, you should keep in mind that contractors often have relationships with specific manufacturers. We discuss manufacturers in the "Choosing a model" section below, but you may want to research the models available from various manufacturers first. Then make sure the contractors you talk to are willing to provide you with something very similar to the brand and model you want. If you follow our advice on choosing a model, you should have a few options in mind.

Choosing a contractor can be a frustrating process, but it is worth making the effort. It is a good idea to get several quotes for any large project since prices can vary widely for the same job. Usually three quotes will be sufficient to determin a reasonable price to pay for the project. If possible, you should try and get quotes from equally qualified firms. The trick is determining which firms to approach. Here are some tips that will be helpful.

• One of the best ways to select contractors is to get referrals from friends or family who have had work done on their homes.
• Check each contractor's licensing for applicability to the job and length of time held. Licensing is administered by the state, county or local city government.
• Check the Better Business Bureau for any complaints against the company
• Check with the office of the Attorney General in your state. The Attorney General's office is responsible for consumer protection and will provide useful information.
• Ask for proof of insurance
• Ask if licensed technicians will be performing the work.
• Ask about the contractor's warranty. Workmanship should be covered as well as all materials installed by the contractor.
• Take advantage of a contractor listing service that prescreens contractors and can place you in touch with qualified firms.

Choosing a model
This is a tough one. Choosing an air conditioner or heat pump is not like choosing a new television or computer. The public at large tends to be less familiar with the features and performance points that are important to a cooling system than those of an entertainment system. The issues that should come to mind when choosing a model are price, performance, reliability, and features.

Price versus Efficiency
The price is important, but should not be the only consideration. Buying the least expensive cooling equipment is usually not the best investment. It is a better idea to consider the operating cost of the equipment as well as the first cost. Because cooling systems last for many years, the operating cost will greatly exceed the first cost of the equipment over its lifetime. If you buy a more efficient system, then over time the lower operating cost will more than pay for the higher first cost. Not only that, high-efficiency cooling equipment improves comfort and air quality throughout the home, and helps reduce air pollution.

Identifying High-Efficiency Equipment
One easy way for consumers to differentiate high-efficiency equipment is to look for the ENERGY STAR® Label. Heating and cooling products with the ENERGY STAR® Label are produced by most major manufacturers and have the same features as standard products but also incorporate energy saving technology. Lists of ENERGY STAR® labeled equipment are available on the Environmental Protection Agency web page.

Manufacturer's product literature is a good source of efficiency information. Most residential cooling systems are rated by Seasonal Energy Efficiency Rating (SEER). The efficiency of heat pumps is described by its SEER for cooling and Heating Season Performance Factor (HSPF) for heating. This information can be found in the product brochures and used as means to compare options.

Reliability
The cooling system you choose today will probably still be around 15 years from now. To avoid frequent service calls and a lifetime of aggravation, you want to get reliable equipment. You should compare warranties offered on various makes and models and consider a good warranty from a reputable manufacturer to be an indication of a reliable product. At a minimum, you will be offered a 1-year limited warranty on your new cooling equipment. Some manufacturers offer longer warranties, up to 5 years on the overall system and 10 years on compressors. Others offer extended warranties at additional cost. Just remember that there are options, don't settle for a minimum 1-year warranty if you don't have to.

Another element of reliability is quality service and preventive maintenance. Be sure that there is a service company nearby that is qualified on the type of system you are purchasing. The best case would be to have factory trained service technicians do all repairs and preventive maintenance on your system. Modern, high-efficiency equipment is complicated, much like newer automobiles, and it takes a great deal of training in order to troubleshoot problems effectively and keep cooling equipment in good working order.

Features and Specifications
When buying a new car, some people are interested in the horsepower and torque ratings, engine block materials, gear ratios, ignition controls, and traction control. Others pay attention to heated seats, cup holders, remote control door locks, and sound systems. The first group is wisely concentrating on the performance specifications, while the second is looking at features, which are important as well. A wise cooling system shopper will compare the specifications as well as the features on a few models before choosing a system. You have to look at product brochures in order to learn about specifications and find out what features are available on which models. These brochures can be obtained from the manufacturers' web sites or from local heating and cooling contractors who sell the brands you are considering. The following list covers many of the specifications and features that differentiate one manufacturer's product from another.

• Efficiency - SEER and HSPF
• Controls - compressor pressure switches
• Compressor type and number of cooling stages
• Indoor and outdoor coil construction and material
• Noise levels
• Condenser fan motor type and speeds
• Warranty

What should be included in the work order or contract
Here is a list of things that you want to have addressed in your written agreement with a heating and cooling contractor. Not all of these items will apply to all projects and you may decide to do some of these things yourself.

It is a good idea to make the contractor responsible for obtaining building permits and meeting building code requirements. Keep in mind, however, that if it isn't in writing, the contractor is not obligated to do it. If it is put in writing, but ambiguously so, the contractor will do it the way he wants.

• Identification of contractor, including registration and tax ID numbers
• Names of any subcontractors who will be used. Check references on these firms as well.
• Completion schedule
• Payment schedule
• Specifications on equipment and materials including brand names and model numbers that you have chosen for the project
• Warranties on workmanship and products
• The following general requirements of the Contractor:
  • Contractor will hand over all equipment installation and maintenance manuals.
  • Contractor must obtain all required permits.
  • Contractor must contact Dig-Safe before outdoor excavating is performed.
  • Contractor must remove the old cooling system and all other construction debris and dispose of in accordance with federal, state, and local regulations.
  • Contractor must perform all work in accordance with state and local building codes.
• Details of what the contractor will do, including:
  • providing a system in good working order;
  • testing and balancing the distribution system;
  • replacing worn piping and ductwork as needed;
  • replacing thermostats, valves, dampers, registers, etc.;
  • cutting and patching ceilings, walls (interior and exterior), and floors, as needed;
  • providing a concrete pad for outdoor equipment;
  • refinishing surfaces to match original conditions;
  • waterproof sealing or caulking of any exterior wall penetrations;
  • flashing roof penetrations; and
  • anything else you expect the contractor to do.
• Total price for the job including labor, materials, and any other charges

Other Thoughts
Your cooling system actually may be a heating and cooling system. If you have a warm-air furnace and central air conditioning, it is likely that both us the same distribution ductwork. Furthermore, the same blower distributes warm air in the winter and cold air in the summer. The point is, when you replace the part of the system it is a good idea to consider replacing the whole thing. If you do so, you will then benefit from a completely compatible integrated system which will provide better performance and reliability than a mixture of old and new components.

There are other aspects to the cooling system which have not been discussed. There are controls, such as thermostats, dampers, and other controls. There are other components such as air filters and condensate pumps which are not part of the air conditioner or heat pump but important parts of the system. There is distribution ductwork for supply and return of conditioned air. All parts of the system should be put in good working order when a new system is purchased. Definitely consider upgrading controls as they will have a lot of impact on how comfortable you are and how much energy you use.

Don't buy an oversized cooling system. First of all, you should take care of all your weatherization improvements before buying a new cooling system. This means adding attic insulation, sealing air leaks, and caulking and weather-stripping windows and doors. Then make sure that the contractor performs a cooling load calculation on the house. The new system may not need to be the same size as the old one. When you make your home more weatherproof, one of the benefits is that your cooling system doesn't need to be as big.

Overseeing the construction process
It is not necessary to stand over the contractor's shoulder constantly while the work is being done. It is necessary to observe all aspects of the work and to be available to answer questions if the contractor runs into unexpected situations. When you are observing the work, think about the items in the contract. If the contractor seems to be deviating from the plan, don't be afraid to question him. Often, the contractor will have to improvise to make a new system fit into an old house. The contractor is usually the best person to decide how to make the new system work. On the other hand, if there is to be a serious deviation from the original plan (for example, the exact placement of the condensing unit, or where a hole will be cut in the exterior wall for the refrigerant line), you should be involved in the decision-making process. This is why one of the most important aspects of construction oversight is communication with the contractor. Make sure that the contractor knows how to reach you and knows that you want to be informed immediately of any problems. Both you and your contractor have the same goal; to get the job done right the first time.

Starting up the system
System start-up includes turning on the cooling equipment for the first time, testing the equipment, and balancing the entire system. You should be present for system start-up because this is when a lot of important activities take place which can not be seen after the fact. You also want the contractor to familiarize you with how the system is supposed to operate and what you should do if there is a problem. The contractor tests the system during start-up. This means that the cooling equipment is run through its full cycle and the contractor takes various measurements to ensure it is functioning properly. You should expect the contractor to test all parts of the system including items that were not changed to ensure that the system as a whole will work properly. The other important part of start-up is balancing. Balancing ensures that all of the rooms in the house will receive the right amount of cooling. In air system dampers are used for balancing. You can pretty much assume that if your cooling equipment is old enough to need replacing, your distribution system needs to be rebalanced. Rebalancing means adjusting dampers or valves until all of the terminal devices (registers and grilles) receive the amount of air that they are supposed to receive. If balancing isn't done correctly then you will have uneven cooling throughout your house.

Warranty Period
Once you are happily through the construction and start-up process, you should enjoy many years of trouble-free service from your new cooling system. If however, problems arise, you want to identify them and get them corrected during the warranty period if possible. You should try to be very aware of the performance of your new system during the first couple of cooling seasons. If the air conditioner or heat pump cycles (turns on and off) frequently for short durations then you should consider this a problem and call the installing contractor or the service contractor who is honoring the installation warranty. If you have cold or hot spots in the house, this is probably a balancing problem and you should also get the contractor back out there to correct it. If you are replacing a very old system with a new, highly efficient system, you can also expect to see a reduction in your energy bills. The exact amount of the reduction can't be predicted because there are so many variables such as how you set your thermostat, how hot it is outside, and what types of problems you were having with the old system. The best measure is how comfortable you are in your home. You can expect that, with your new energy efficient cooling system, you will be buying more comfort for each dollar you spend on energy. If you are not more comfortable and spending the same amount on energy, there maybe a problem with your new cooling system.