Not just a heat heater: air conditioners remove moisture from the air and also filter allergens nearly as well as most air purifiers. Air conditioners take the sizzle out of hot, humid days by blowing warm air over metal coils filled with a refrigerant. This not only lowers the air temperature hut also condenses the water vapors in the air, producing a cooler, drier indoor climate.

Aside from added comfort, air conditioners provide protection from several health threats, especially heatstroke. A life-threatening condition, heatstroke usually develops over the course of several scorching, humid days and causes the body to lose its ability to release heat. Sweating stops and the body's temperature soars. However, spending just a few hours a day in an air-conditioned room can short-circuit this dangerous process. People who suffer from diabetes or heart disease and those who take such medications as anti-histaniines, diuretics, beta-blockers, and vasoconstrietors are at the greatest risk of developing heatstroke.

Air conditioners are also a boon for people who suffer from allergies or asthma. As the units cool the air, they also filter pollen, mold spores, and dust, all of which can trigger allergic and asthmatic reactions.

If air conditioners aren't well maintained, they can cause some of the very problems they otherwise prevent. A dirty air filter can harbor pollen, fungi, and bacteria and allow millions of microorganisms into the room, possibly triggering an asthma attack, irritation of the eyes, nose, and throat - even flu like illness. Proper maintenance will minimize these risks.

About every two to four weeks, vacuum the air filter, and then wash it in soapy water. Be sure to let the filter dry completely before reinstalling it. You may also want to spray it with a disinfectant to keep it free of mildew. If the air conditioner uses disposable filters, remember to replace them at the recommended intervals.

Air conditioners in large buildings can pose a more serious threat because they use reservoirs of water that can harbor harmful bacteria. When Legionnaires' disease struck a an American Legion convention in Philadelphia in 1976, epidemiologists found colonies of the deadly Legionella pneutnophila bacterium in the air circulated b1 the hotel's air-conditioning system. Other organisms that grow in large air-conditioning units can trigger hypersensitivity pneumonitis, also called allergic alveolitis. The condition is caused by inhaling microscopic organic dusts, which inflame the air sacs of the lungs and can eventually interfere with normal breathing.

The air conditioners in our ears can pose problems of their own. The interior of the units are hot, moist, and dark - an ideal breeding ground for fungi and mold spores.

If you are allergic to mold, opt for the fresh air rather than the re-circulated air setting, aim the air vents away from your face, and crack open the car windows for several minutes after you turn on the air conditioner to allow any microorganisms to escape. If the problem persists, you may want to have a qualified mechanic treat the air conditioner with a disinfectant which will keep it mold free for about three months.