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Air Conditioning for The Home
by Dr. Oneida Cramer
The news in air conditioners lies behind the cool air and electric bills. It?s in the maintenance of good air quality because air conditioning provides the best filtration of the air you breath inside your home, according to Vicki Chase, marketing director of Frymire, a company owned and operated by the Frymire family since 1950. And finding the right air conditioning system depends as much on your style of living as your home.
?It?s important that we know the number of people that live in the home,? said Chase. ?When we go to a home, we look around to see if the people are hunters, golfers, bowlers, or if they have these game rooms that are built to entertain.? Or the people might be empty nesters or someone bothered with allegories.
?When a person is considering a new home comfort system, depending upon what efficiency they decide to go with will dictate what their utility bills are going to be,? said Chase. In other words, a high efficiency system will cost more than a standard system, but it will generate lower utility bills. And you can count on a yearly rate increase in utility bills, said Chase.
Another factor to consider, when thinking of utility bills, is the proposed deregulation of the Texas electric industry, passed by the Texas legislature on May 27, 1999 and scheduled to begin on January 1, 2002. Under the provisions of Senate Bill 7, there will be a mandated 6 % decrease in rates for residential and small commercial customers at the outset of the deregulation period followed by a five-year cap on rates. At that time, customers will get to choose their power supplier. Until then, utility companies will continue serving retail customers as dictated in the present regulated system.
Besides Texas, 24 other states have passed legislation allowing for competition after Congress opened up the possibility in 1992. New Hampshire was one of the first states to pass a deregulation law, which began a two-year pilot program in 1996. Competition in California started January 1, 1998. But this summer?s skyrocketing rates in San Diego has created a crisis situation and triggered a new round of discussion by lawmakers. Other states are just beginning to install deregulation or have scheduled transitions for the future. Nevertheless, deregulation is ahead for Texans. And homeowners should consider that an air conditioning system purchased today would still be functioning in 2002 because air conditioners conservatively last from 10 to 20 years, according to Ray Rodden, owner of Hooper Air Conditioning.
So, it?s crucial that the system be sized correctly and maintained properly for maximum efficiency. For instance, an undersized unit may run for long periods of time and still not cool the home properly. On the other hand, an oversized system will cool the house with cycles that are too short to remove humidity, according to Richard Henderson with M.B. Kiser Heating and Air Conditioning. An oversized unit will make a home feel clammy and uncomfortable. And the moisture that builds up on the coil can cause mold and mildew and shorten the life of the unit. Note that an oversized unit should not be confused with high efficiency air conditioning that is sized correctly.
?A layman is unable to determine the correct size of an air conditioning system,? Henderson said. ?It?s totally dependent upon the structure of the home, how much insulation is involved, how much glass, which way the home faces, whether or not there?s inside shading, whether or not there are trees that will be green in the summertime to shade from the sunshine.? It?s also dependent on the color of the roof, the insulation in the attic, where the ductwork is located, how much ceiling you have, how much floor, and what kind of flooring. ?All these things come into play.?
?In fact, most people do not have a basic understanding of what an air conditioning system does,? said Henderson. ?Most people have the feeling that this thing in some fashion pumps cold air into your home. And that?s the wrong concept.?
?An air conditioner removes the heat from the room air and puts it outside,? said Henderson. An air conditioning system is made up of two basic components: an outdoor compressor and an indoor evaporator. Connecting the two components is a circuit of tubing that?s sealed and filled with refrigerant, which is a volatile liquid capable of changing from a gaseous to liquid state and back to a gaseous state over and over again. The refrigerant is a liquid in the condenser. As it flows indoors and through the coiled evaporator, the refrigerant becomes a gas. Just as evaporating sweat cools our bodies, the evaporating refrigerant cools the coil to 42 degrees F to be exact. At 42 degrees F, the coil sucks heat and moisture out of the incoming room air. So, the outgoing air is 20 degrees cooler than when it came in. The heat taken up by the gaseous refrigerant flows through the tubing out to the condenser, where the compressor forces the gas back to a liquid and the heat is released to the outside.
To comply with a 1990 Clean Air Act, the US is committed to phasing out the production of the current refrigerant, R-22. Puron, a brand name for R-410A, is touted as the compound of the future. Carrier offered one of the first air conditioners designed to use Puron; but today, only 0.1 of 1% of air conditioning units use Puron, according to Henderson. And manufacturers continue to make and market systems for R-22, indicating a long phasing out period, according to Chase.
Replacing an air conditioning system properly is an expensive project that ideally involves an entire system including the evaporator coil, the condensing coil, the refrigerant tubing, electrical network, and, perhaps, even the ductwork.
Choosing between flexible ducts and metal ducts sparks another controversy. University Park building code does not allow flexi-ducts, so homeowners in University Park have no choice. In Highland Park and Dallas, where residents do have a choice, Henderson recommends metal ductwork to avoid damage from animals or obstacles punching holes into the ducts. The quality in flexible ducts is better today than fifteen years ago, say Chase and Rodden, who both recommend the flexi-ducts. Flexi-ducts spring back after being squeezed; metal ducts just stay flattened, says Rodden. And while metal ducts can be put in problem areas, the relatively inexpensive flexi-ducts offer a substantial savings to the customer. Also for good air quality, ductwork should be kept cleaned, said Chase, who does not recommend cleaning a duct unless necessary, a problem that can be spotted with signs of mold on the vents.
To maintain the most efficient cooling, keep the thermostat at a comfortable temperature. Don?t reset the thermostat to the minimum setting in hopes of forcing down the temperature, recommends Henderson. An air conditioner will return air that?s only 20 degrees cooler than existing room air. And in the intense heat of a Dallas summer afternoon, the air conditioner may be working at maximum capacity. But when set at the lowest setting, a thermostat reading may cause the unit to freeze up later in the day after room temperatures cool down too low.
Insulating against the heat can be accomplished with measures, such as caulking all the cracks, shading the windows, or installing insulated windows, said Rodden. But the most important thing a homeowner can do to conserve energy in an air conditioned home is to change the air conditioner?s filters as often as required?once a month if necessary, adds Chase. Most air conditioning problems stem from dirty filters that clog airflow and strain the unit. Although homeowners may hose off a condenser that?s been turned off, be careful not to touch the electrical part, according to Rodden. In fact, a service agreement with a heating and air conditioning company is the most fail-safe way of maintenance.
?It?s important to get to know the business with which you are dealing,? says Chase, ?because the trend today is for conglomerates to come in and buy up the heating and air-conditioning companies.?
Dr. Oneida Cramer
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