Let us talk a little about central air conditioning and heating. Different times of the year we have different temperatures. In the summer time the house is going to get hotter than it would in the winter time. This is obvious, so we will need a system to remove heat in the summer and a system to heat up the cold air in the winter. This is where the combined central air conditioning and heating system come into play.

Central air conditioning and heating systems are taking over the old school window units. This is because central air has a vent that is going to every room in the house, office, or building. The air gets sucked in through the air handler then the air reaches the vents in other rooms and such through air ducts. Central air systems also have an advantage over the window unit because it operates much quieter, since the condenser that is the noisiest part of a central air system is located outside. The inside unit called the air handler, is usually located up in an attic, or hidden behind a closet door with a return vent on it. Another upside that central air and heating has on the window unit that again, it is outside, meaning it is not going to be blocking the view outside at all. And most of all you can switch from heat to air with just the touch of a button. Even though there are separate systems out there like just central air and just central heating but I am not talking about those in this article.

Many people still use the window air conditioners, which will work great just to cool a 500 square foot room, but when it comes to winter time, you aren't going to be using your window unit, you would probably be using a portable heater. If you have a house with four bedrooms you would need a lot of window air conditioners and portable heaters wont you? But this is getting to be a thing of the past.

Almost every new home built today is built with central air conditioning and heating installed. I mean could you imagine that you were looking to buy house and when the realtor shows you this beautiful house with all new cabinets and appliances but doesn't have central air conditioning and heating installed? That isn't very likely to happen nowadays. Central air and heating are just as much part of a home as a kitchen and bathtub.

How do I choose a Central Air Conditioner?

So say that you are building a house, or just simply would like to upgrade from your old AC unit, you would need to know what kind of central air conditioner you would want the contractors or whoever to install. First thing you would want to take into consideration would be the SEER (Seasonal Energy Efficiency Ratio). The way that SEER is calculated is by dividing the cooling capacity of an air conditioner that is running constant by the electrical input that's required to run it. And then it is named by number. The higher the SEER rating of the air conditioner the more efficient the unit will run, and the more you will save on your electric bill. As of the beginning of the year 2006 the United States requires that all central air conditioners have a SEER rating of at least 13. On another note, window air conditioners aren't required to have a 13 SEER rating, they are usually SEER 10, so this is another reason why central units triumph over the window unit.

Another thing that has to be determined is what size unit your house is going to need. There are very many factors that help determine the ton to square foot ratio for cooling. Some of these are how well the house is insulated, like what kind of windows it has, how many stories the house has, and of course what the local power rates are. For example, let us say that we have a 1200 square foot house in Arizona just off a highway, there are no trees around the house and it barely gets cloudy in the city that your house is in. This house might require a 3-3½ ton air conditioner. Now say you have another house that is in Northern Florida, on a nice block that has many trees surrounding your house, the house was just built a couple months ago with insulation inside the drywall, this 1200 square foot house might only need a 2 ton air conditioner. Though the temperature outside, according to the weather forecasts might be fairly the same, the insulation surrounding the outside and inside the house is very different.

Last thing I want to talk about central air conditioning systems is FREON. Currently as of now (2008) the EPA is slowly phasing out air conditioners that use R-22 (ozone depleting refrigerant). In 2010 they will stop manufacturing air conditioners that use R-22. All air conditioners after December 31st 2009 that are manufactured will be using non-ozone depleting refrigerant, such as R-410A. Some models are already selling air conditioning systems using R-410A. What does this mean for the old R-22 systems? They will continue the production of R-22 until the year 2020. After that all of the R-22 air conditioner systems will be serviced with recycled R-22. Now if every HVAC certified technician obeyed the law (you HVAC guys know what I mean) we could service these systems for about 30 years until the compressor just can't kick no more.

Can't I just convert my old R-22 system into as R-140A system?

The answer is no, simply because the pressures that are involved in the R-410A are about twice as much as the old R-22. The new Ozone friendly air conditioning systems and components are specifically designed to stand this kind of pressure. The older ones (before 2010) are not.

So take all of these factors into consideration before purchasing a new central air conditioner and heater, especially the SEER rating.