How to choose the right air conditioner

If you're in the market for an air conditioner this year, you'll find some nice new features. Many units have been designed to blend more compatibly into room decors, and technological advances have made them more energy efficient as well. Since consumer demand for energy-saving models has increased dramatically over the last 10 years, manufacturers have come up with more efficient compressors and motors, better air circulation systems, and improved evaporator and condenser heat-transfer systems. Because of these improvements, the new models use an average of 18 percent less energy than their 1972 counterparts. And they can control and regulate the temperature much more precisely.

Several manufacturers have designed new units that are down-sized and weight-reduced to minimize bulk. And many units feature not only high energy efficiency but quiet operation. Some come with built-in timers - a boon for working people who don't want to run their air conditioners all day long. They can set the timer for 4 p.m., for example, in order to have the place cooled down before they arrive home from work.

As an aid to shoppers, the Association of Home Appliance Manufacturers in Chicago has put together a useful booklet called ``1987 Consumer Selection Guide for Room Air Conditioners'' which includes a cooling load estimate form for calculating cooling capacity, plus a directory of new room air conditioner models with the energy efficiency rating (EER) and certified Btu/hr. cooling capacity listed for each unit. Btu/hr. (British thermal units per hour) refers to the amount of heat and moisture transferred out of the room in one hour. Larger ratings indicate greater cooling capacities.

This guide gives all the shopping information you need and explains what factors to consider as you comparison shop. It can be ordered for $1.50 from AHAM, 20 North Wacker Drive, Chicago, IL 60606.

In the store, the booklet advises, look for a unit with a high EER, since it will use less electricity and cost less to operate. A bright yellow EnergyGuide label shows each model's EER, its cooling capacity, and how it compares in efficiency to other models of similar capacity.

Cooling capacity is the most important factor to consider when choosing your air conditioner, says AHAM spokesperson Marian Stamos. A unit with too little cooling capacity won't deliver enough cold air, but a unit with too much cooling capacity won't dehumidify the air adequately and the result is chilly, humid air that feels cold and clammy. At home, says adds, you can save energy by following the manufacturer's use-and-care instructions carefully, plus these useful tips:

Reduce the heat generated in the house by covering windows exposed to the sun, turning off lights and appliances not in use, avoiding the use of cooking or laundry equipment and the taking of hot showers during the hottest hours of the day, and by using heat-producing appliances such as irons and ovens at different times.

Prevent cooled air from escaping by closing off unused rooms, keeping doors and windows tighly closed, and closing all unnecessary openings such as fireplace dampers.

Maintain the efficiency of your unit by by cleaning the filter several times during the summer, and the condenser (outside coil) once every two or three years. Do not restrict the air flowing in or out of the unit, and locate it on the north or east side of the house, if you have a choice.