Though it's still freezing in many parts of the country, there's big news when it comes to air conditioning that you should know before it's time to crank up your home cooling system.

As of Jan. 23, 2006, the U.S. Department of Energy requires manufacturers of air conditioners and heat pumps to produce equipment that has a Seasonal Energy Efficiency Rating of at least 13.

SEER is the number that the DOE uses to measures the efficiency of air conditioning equipment. SEER is to air conditioning what R-Value is to insulation and, like insulation, the higher the SEER rating the more energy efficient the equipment.

Prior to Jan. 23, the minimum efficiency standard was 10 SEER -- meaning that manufacturers were required to produce equipment that met or exceeded 10 SEER.

The U.S. government wants Americans to use less fuel to cool their homes and the nearly one-third increase in the minimum standard is projected to reduce energy bills for homeowners up to 30 percent over the current 10 SEER units.

Will the new 13 SEER rating affect you? It will if your system has a SEER of 12 or less. But there's no need to panic, given that existing systems may remain in use and repaired when needed. However, keep in mind that replacement parts for 12 SEER and lower units will become increasingly sparse, thus eventually requiring system replacement with a more energy efficient model.

You may also be required to alter or upgrade your old furnace.

Most air conditioning systems consist of two major components: the outdoor unit, referred to as the "condensing unit" or "compressor," and the indoor component called an "evaporator coil" or "coil case," which is part of the furnace.

The size of the coil case at the furnace has a direct relationship to the SEER rating and the condensing unit. Thus, if the inside and outside units are not compatible, you may need to replace both units in order to maintain system compatibility. This really isn't necessarily bad news since it doesn't make a whole lot of sense to have a new, more energy-efficient air conditioner and a gas-guzzling furnace.

Regulations aside, you may not want to wait for your old energy-guzzling air conditioner to fall apart before upgrading to a new more energy efficient model. Depending upon the climate where you live, how often you use your air conditioning, and how long you expect to live in your home, there may be lots of money (and energy) to be saved over the long haul. A 13-SEER unit will deliver about 23 percent energy savings compared to a 10-SEER model and about 8 percent energy savings compared to a 12-SEER model. Actual savings will depend on the age, efficiency and condition of the unit being replaced.

Therefore, if you live in a warm and humid climate, use your air conditioning often and expect to live in you home for a while, the higher the SEER rating, the better. Even though equipment costs increase as SEER ratings rise, you'll be money ahead in the long run. And as a bonus you'll be consuming less of our precious natural resources.

How do you determine which SEER is best for you? A good place to begin is by consulting your local utility company. They can help you determine the approximate portion of your utility bill that is devoted to cooling. A professional heating and cooling contractor can use this information to determine payback and what makes the best economic sense.

To get the best bang for your cooling buck, look for equipment that has earned the Energy Star seal of approval and don't forget to check with you local utility company for rebates for equipment upgrades.

In addition to saving money, new products are quieter than older, less efficient models to create a more relaxed home atmosphere. Some models have been tested at 69 decibels, which is quieter than an average running refrigerator. In addition, new models use an environmentally sound refrigerant.