The purchase of a residential or commercial central air conditioning unit can be a sizable investment. There are many factors to consider prior to diving into these waters. For those living in the deep South and desert Southwest, air conditioning is not so much a question of if, but more along the lines of how much and what kind. While the initial expense for central cooling may seem high, over the life of the system, much of that is recovered with lower utility bills. Those in more northern latitudes need to analyze the costs and benefits thoroughly. While over 85 percent of all American homes are air conditioned, it may not make sense to purchase an expensive central system for 10 or 12 uncomfortable days each year. The information that follows describes the pros and cons of the various air conditioning options available and how they work. There are also details about government-imposed regulations and the ratings that all newly produced air conditioning systems must attain in order to comply.

From this data, readers can determine whether or not converting to central air conditioning or updating to a newer system makes economic sense. There is also a section describing the best ways to find these systems at the lowest possible prices. Buying an air conditioning unit is not like purchasing a flat screen television; for instance, where personal size preferences and optional bells and whistles come into play. Since it is more a function of accommodating a specific space and geographical location, the choices are relatively well defined. Keep in mind that, essentially, all AC units are electric, even those that work in conjunction with natural gas and propane furnaces. There are some exceptions, but they are now so rare that they are not part of this discussion. Air conditioning systems are rated in tons. One ton equals the required energy to produce 12,000 British thermal units (BTUs) per hour. A BTU is the amount of energy needed to increase the temperature of a pound of water one degree centigrade.

Larger systems use tons to denote capacity and smaller ones use BTUs. The size of the space to be cooled, the outside air temperature, and the quality of the building insulation have a lot to do with system sizing. A split system is the most common type of central air conditioning system for homes. It relies upon an indoor air-handling unit that often shares duties with a heat producing furnace. It also shares the same distribution and return air ducting as the heater, making the combination more attractive both economically and aesthetically.how to fix a broken window ac unit The compressor and condenser unit is mounted on a concrete pad outside. used central air conditioner units for saleIt pressurizes gas refrigerant into liquid and sends it to the air handler unit, typically in the basement where the evaporator changes it to gas, causing the coil to become cold. air handling unit for sale

The warm air from the living space is drawn through return air ducts across the evaporator coil and sent back to the residence. The entire system recirculates the same air and refrigerant constantly. Central air systems that are reasonably new add to the resale value of most any property. They are the most energy efficient option when compared to alternatives that cool the entire living space. It is important to replace the filters on schedule and to have annual maintenance performed. Since most commercial installations do not provide the space required for a split system, rooftop mounted air conditioners solve the problem. A smaller version of this design is often used on mobile homes and recreational vehicles. The flat roof is perfect for these systems, where the air handler, compressor, and condenser are all incorporated into the same unit. An AC system perched on a building roof is also easy to access and is not taking up valuable floor or storage space. Another advantage to this design is that in the event an increase in cooling capacity is required, it is easy to add an additional unit to supplement the first.

Commercial roofs nearly always have the required space to position additional equipment next to the original. The same ducting is usually sufficient to handle the additional airflow. The most commonly used alternative to central air conditioning is the window or room air conditioner.. These are freestanding units that fit into a typical window opening. The lower half of the window is positioned on top of the air conditioner and furnished side panels are extended to maintain a reasonably tight environment. A specific casement design is available for that style of window. It is also an option to create a separate opening in the wall to avoid using a window altogether. Window units offer the advantage of isolating the cooling function into one or several rooms only. They are less expensive to purchase and do not require any additional or supplemental ductwork. Maintenance is limited to cleaning or replacing a filter. On the downside, while the noise these units produce has been greatly diminished over the years, they are still quite a bit louder than central AC systems.

As they are not subject to the same environmental regulations as central air conditioners, they are not as energy efficient. Portable air conditioners offer the useful advantage of being able to relocate easily. They are mounted on casters and simply roll from room to room. Another advantage is that they can be positioned closer to or further from a specific location within the room, an option not otherwise available. That option is only limited by the length of the exhaust duct that should be connected to an outside vent, much like a clothes dryer. Many people neglect to discharge that exhaust, which then limits the cooling capacity of any portable. Like other types of air conditioners, the portable versions must eliminate condensation produced in the cooling process. This is done by gravity with a separate drain hose, by periodically emptying a reservoir, or by attaching a condensate pump. Check the specs on any unit prior to purchase. The governments of the United States and other more advanced societies now regulate the efficiency of air conditioning units.

It has forced the manufacturers of central air conditioning systems to continuously improve the efficiency of their products. Older air conditioning systems are much less efficient than current models. Replacing a 10-year-old unit could save 10 to 20 percent in cooling costs. Central air conditioners manufactured after January 26, 2006 must achieve a Seasonal Energy Efficiency Ratio (SEER) of 13 or higher. A SEER of 13 is 30 percent more efficient than the previous minimum SEER mandated level of 10. The SEER number is assigned to all central air conditioning units as a way to compare relative electrical consumption and efficiency. In simple terms, it is the ratio of BTUs to electrical wattage, utilizing constants of a 95-degree outdoor air temperature, cooling to 80 degrees at 50 percent humidity. Keep in mind that window units and portable air conditioners are exempt from this requirement. Expect them to produce a SEER rating of about 10. You may be surprised to learn that the best way to purchase a central air conditioner or any other type is on eBay.

Start at the eBay homepage and locate the search field found on any page. Then, enter your preferred search terms. For instance, try entering "evaporative cooler&" into the open bar and click "Search." You are then redirected to a different page with all available offerings. You can then specify the type, brand, new or used condition, price range, and more to narrow down the number of results. Glance at eBay's Search Tips for some other pointers on searching the website. Air conditioning equipment can be costly, even on eBay. One way to be certain that a family member or friend can get something they absolutely need is to organize a group and use eBay's Group Gifts feature. It is easy and saves a lot of coordination time. Just determine which item you want to give. eBay then allows you to contact other people using email or Facebook who want to participate in the gifting. They soon receive detailed instructions and no one gets charged until the full cost of the gift has been raised.

Once all of the money has been committed, eBay notifies you and you can forward the gift. Furthermore, there is no charge for this service. As the price of electricity continues to rise, it is nice to know that air conditioning equipment has made great progress over the last 20 years to keep stride. There is no question that older AC units can be responsible for significantly higher bills in the summer than winter bills from heat in most temperate climates. If electricity expenses have become exorbitant when running the air conditioner, it is time to consider replacing that aging central air system or converting over from older window units. For those who live in a cooler climate, with the increasing temperatures most locations now experience, a newer energy-efficient window unit might just be the perfect solution. Shoppers are now taking advantage of the Internet to find virtually anything that they used to try to find in local stores. Rather than calling and driving all over town, having to deal with store sales staff, and paying much higher prices, the Web enables anyone with a computer or smartphone to compare and buy without leaving home.