Undoubtedly, one of the biggest factors in determining whether you go with a central air conditioning system or a window air conditioner is the one that has to do with the difference in cost between the two systems. Another factor to consider in deciding between which type of system you need is whether you are planning on cooling an entire house or just a couple of rooms. While either window units or a central air conditioning system will do the job, common sense and financial considerations will almost certainly guide you to the most practical solution to your cooling problem. Let’s look at some things you’ll want to consider in making your decision about central A/C vs window A/C.
If you are going to use a central air conditioning system to do your cooling, it is almost surely a fact that installing a central air conditioning system to cool only a couple of rooms in your home is not going to be a practical decision for a couple of reasons. First of all, your home will probably have ventilation ducts installed throughout to duct warm air from a central furnace. Utilizing those ducts to cool only one or two rooms, while possibly saving money in operating your cooling system it is going to depend on where your thermostat for your heating system is located. If it’s in one of the rooms you plan on cooling, then a central air system may work in this case. If, on the other hand, the thermostat is located in one of the rooms that you’re not planning on cooling, then the cooling system is not going to work effectively or efficiently for you. On this subject, remember also that you’re probably going to have to replace your present thermostat with a newer one, especially if it is more than a few years old.
If you do not have a central furnace with ducts in most or all of your rooms, then you will have to retro-fit your home to include duct-work to the various rooms. Also, if this is the situation, it is impractical to only use a central system to cool a couple of rooms due to the cost of installing both a central cooling system as well as ducting.
On the other hand, if you are planning on cooling your entire living space, the use of multiple window air conditioning units in rooms throughout the house is probably not going to be a practical method either. In this situation, routing cooled air throughout the living area through a duct system is probably going to be the most efficient method to achieve a comfortable level of cooling throughout the house. A number of factors enter into determining the efficiency of using multiple window units. One such factor is the location of the windows in relation to doorways or other openings between rooms. This has a large bearing on whether cool air produced by a window unit can adequately cool more than one room. Another factor is the adequacy of the wiring in the house to support the increased electrical load that the multiple window units will place on the home’s electrical system. This could easily be an expensive problem if the house were older and not equipped with a modern electrical system that would support the additional amperage load that would be placed on the wiring with multiple window units installed and maybe even running simultaneously. While a central air system might also require an increase in electrical service required by the home, it is much less expensive to increase the service to the house by increasing the service available than it is to increase that service as well as doing rewiring of some or all of the electrical wiring in the house!
At the very least, if you are considering adding air conditioning to your home, call in at least one, and hopefully two or three, HVAC (heating, ventilation, air conditioning) contractors, explain what you want to them and ask their opinions and solicit written bids on the work that you decide on. Then and only then can you make an intelligent decision on which way to go to solve your problem.