Having central air units is becoming more and more common in homes as homeowners have realized the comfort and convenience of central air conditioning.

While they are generally worry-free, they do occasionally need to be replaced, and there is basic maintenance you should complete in order to keep your unit running well and at its highest efficiency.

If you're replacing a central air conditioning unit, then there are some features you should consider. In today's market, it makes sense to look for an Energy Star unit – one that is highly energy efficient.

Many systems are very efficient today, so you should weigh the options available in price versus efficiency.

You'll also want to consider the power of the unit, or BTUs. Technically, one BTU is the amount of energy needed to raise the temperature of one pound of water exactly one degree on the Fahrenheit scale. In practicality, it's a measure of how much energy power your air conditioner has. BTUs have nothing to do with efficiency, but do have to do with cooling power.

When deciding how many BTUs your central air conditioning system should have, consider the number of windows in the house and their size, how much insulation is in the home, the climate in the area, the amount of shade that covers the house and for how long each day, and the direction the home faces. All of these things will affect the amount of work your system will need to do. Typical systems vary between 36,000 BTUs and 72,000 BTUs, so some homework is advisable to see what is right for your home.

Choosing a central air conditioner that is too small or the home or not powerful enough will result in higher energy costs and inefficiency in the system.

You'll also want to look for warranty, Some air conditioning systems carry long warranties; up to ten years. Other warranties are much shorter, but the units may still have a great reliability record. Be sure to do your homework before you decide.

Other features you may consider are the weather protection systems for the outdoor units and environmentally friendly refrigerant.

Maintaining the central air system is not complicated, but it is easy to forget. Indoors, if you have a forced air system, then you need to change the filter frequently so that it can run at the highest efficiency possible.

Outside, you should look at the compressor each year. First, clean it off with a broom and/or garden hose spray. Any dirt needs to be washed off, any leaves or weeds piled on the compressor should be removed, and all weeds, dirt and rocks that are near the compressor or heat pump condenser should be eliminated. Keeping the condenser clean is the single easiest and most effective maintenance anyone can do for a central air system.

You should, however, also remember to look at the fins of the condensing coils to see if there has been damage. Looking at the fan and lubricating the fan bearings are also important annual tasks to perform.

A professional can accomplish these tasks, or the homeowner can learn to “do it yourself” on the central air conditioning maintenance.

Interested in a central air unit for your home? Get your project started by submitting a free BuyerZone request for air conditioning price quotes.