A common misconception about air conditioning equipment is that Brand Name is the best indicator of quality. While it is true that some brands are better than others, this is not the main criterion you should use when making your buying decision. You may do yourself a great disservice if you overlook this.

The most important factor regarding central air conditioners and heat pumps, without exception, is the quality of the installation.

A high-end air conditioning system installed in an unprofessional manor, without regard for quality of installation or proper sizing will not perform any better than a low-end system installed with emphasis on the quality of the installation. Furthermore, using the above example, the operating and maintenance costs associated with the high-end system may very well exceed that of the low-end system by a large amount over the life of the equipment.

These expenses will show in increased monthly energy costs, maintenance costs, and equipment breakdowns. There are also concerns about indoor air quality, and noise.

One of the benefits of a properly sized air conditioning system is humidity control. The operating characteristics of air conditioners is similar to dehumidifiers. The evaporator coil temperature is below the dew point temperature when in operation. This results in moisture condensing on the evaporator and reduces the moisture content in the air. This results in lower humidity. The run cycles of an over sized air conditioner will be too short for this dehumidification process to occur.

The run cycles of an undersized system will be too long and may keep humidity levels too low. This system will loose a lot of its capacity to the dehumidification process and only cool effectively when humidity is very low.

Maintenance and repair costs can be higher than normal on an over sized air conditioner. There are components in air conditioners that require replacement from time to time because they wear out. For example the compressor contactor. The contactor is the device that operates the compressor. Each time the compressor starts, the contactor closes. The more often the compressor starts and stops the faster this part will wear out.

The compressor is another example. It is common knowledge the greatest amount of wear on a car engine is at start up. The same is true of an air conditioner compressor. There is oil in the compressor and each time it cycles off the oil drains from the bearings and gets picked up again at startup. Because there is less oil for lubrication at startup, this is when the greatest amount of compressor wear happens. If your air conditioner cycles on and off 4 or 5 times per hour instead of the normal 2 or 3 times per hour it only makes sense that this causes more wear on the compressor.

These are only some of problems associated with over sized and undersized air conditioning equipment. There are other complications that add to these problems and cost you more money. So when shopping for a new air conditioning system get more than one or two prices and make sure the contractor does proper load calculations so you can avoid these problems.