Most modern residential air conditioners rely on hydrochloroflurocarbons, or HCFCs, in order to operate. There are several kinds of HCFCs on the market. The one most often encountered in contemporary systems is called HCFC-22, or R-22.

So long as R-22 remains hidden in your air-conditioning system, it is not a problem. But when it escapes, many scientists and lawmakers believe it harms the environment by affecting the earth's ozone layer.

The ozone layer is characterized as a kind of protective wrap. Global warming, if it really exists at all, is blamed by some on this ozone depletion. Also, blamed on this is the reported increase in skin cancer cases.

Ten years ago, the federal Clean Air Act was amended to begin a mandatory phase out of the production and use of many ozone depleting substances, including R-22. R-12, which is usually found in auto air-conditioning systems, is also covered by the phase out, as are many substances that are less familiar to most people. The ban is more gradual for R-22 than it is for R-12.

By the year 2010, no U.S. company may manufacture a product that relies on this substance. In addition, R-22 cannot be manufactured or imported except for use in equipment manufactured prior to that year. There is a total ban on production and importation that becomes effective in 2020.

Air-conditioning manufacturers intend on remaining in business after 2010, and in fact most of us really want to remain cool after 2020. Thus, there is a need to develop a new refrigerant that will not harm the environment and that is not dangerous to use. And a possible contender has now been found. This contender is a new refrigerant called "Puron." Puron might be to those of us who enjoy cooler temperatures what Equal is to those of us with a few pounds to shed and a sweet tooth.

Puron is a brand name for a refrigerant called R-410A. Carrier markets the refrigerant under this brand name. Carrier has been making Puron based air-conditioning systems for three years. Other manufacturers are now beginning to use it in their air-conditioning systems as well.

To many in the cooling industry, Puron is already viewed as the universal replacement refrigerant for R-22, to be used in residential systems. This belief is supported by the fact that eight of Japan's top air-conditioner manufacturers will introduce Puron systems to the public this year.

Puron is reported to be an efficient product, in fact slightly more efficient than the R-22 it is replacing. It is nonflammable and generally viewed as nontoxic.

The biggest problem with Puron appears to be that a specially required lubricant, called polyol ester, can absorb a great deal of moisture during system operation. Moisture can be problematic to air-conditioning systems and as a result, special care is needed to properly dehydrate Puron systems during installation and maintenance.

Carrier has reported that it has addressed this issue with special training and certification programs for dealers and technicians. In fact, Carrier claims that their Puron systems have the lowest rate of compressor failure, compared with traditional R-22 Carrier systems.

Currently, Carrier offers three models that rely on Puron: the 38TSA, 38 TXA and 38TZA. A heat pump, and two fan coils are also available from the company.

Other manufacturers, such as Bryant, are beginning to market Puron based air-conditioning systems as well. Soon, just about every company will likely sell a Puron system. If reliability and performance continue, it might very well be that Puron will become the air-conditioning industry standard.

If your system is working well, you probably don't want to make any changes at this time. After all, Puron systems are still new, and advances are sure to follow. Most of us avoid purchasing new automobile models the first year they are available. For the same reason, it might be advisable to put off a Puron system purchase as well.

But, if your system is having problems, you might want to consider replacing it with a Puron system. In roughly 10 years, the availability of R-22 will be reduced, which means refrigerant costs, and related servicing costs, will increase. Though a Puron system purchase may be somewhat risky, it may also prove to be a good investment, and one that will support a better environment.

In any event, remember the word "Puron." You will probably be hearing more and more about Puron in the next few years.

The information provided in this column is written by Stuart Lieberman,a practicing environmental attorney, and is for general information purposes only. It is not legal advice and should not be used in place of legal advice.

Stuart Lieberman, Esq., and IRED.Com, Inc., will not accept any responsibilty for any reliance on the information in this column or any damages whatsoever resulting from reading this column.