When his air handler broke down in June, Angie's List member Jamie Sculerati of Land O' Lakes called Bay Area Heating and Cooling Inc. in Largo to fix it the same day. "It was your typical no-notice, must-be-fixed-soon emergency," Sculerati says, due to the record-breaking summer heat. It's one reason heating and air conditioning is the most-reported category on Angie's List in Tampa.

Highly rated HVAC contractors say the region's heat and humidity puts an excessive strain on air-conditioning systems, especially since they often run for 10 or 11 months at a time. But homeowners have options to keep the air flowing and humidity under control during even the harshest seasons.

Kaylon Mishkel, general manager for Lloyd's Heating & Cooling in Tampa, says drain lines are an important concern, since they funnel condensation out of the house and can back up into the unit when they clog. "We encourage our customers to put bleach or algaecide [a chemical that kills algae] down their line on a monthly basis," Mishkel says. "Go outside and check to see if water is coming out. If there's no water flowing out in a humid summer, you've got a problem."

Seasonal residents also can run into trouble if they elect to leave their Florida homes without air conditioning while they're away. "You can get mold in your house if you leave it vacant for several months without A/C," says Kenny Parr, owner of The Dan Wright Corporation in New Port Richey. "Some people put in humidistats so the system will activate if the humidity gets over a certain level. That little bit of running won't cost you a lot, but it could save your carpets, sofa and interiors."

Improperly sized equipment is also a big problem, says Chris Gourdine, general manager of Bay Area Heating and Cooling. A too-small system might never effectively heat or cool the home, and a too-large system will use more energy but never run long enough to pull humidity out of the air, he says. He recommends having your installer perform a manual load calculation, which measures the amount of heating and cooling a house needs, and the size of HVAC unit required. It should take into account not only building size, but also materials, windows and insulation.

Air handlers also can fall victim to very locally specific problems. "We've seen A/Cs rendered totally unusable because of ants or lizards in the contactors outside," Mishkel says. "If a gecko or snake crawls into the drain line, it can block it completely and cause problems."

Professionals advocate getting regular checkups. "Your system is like your car; you always change the oil, check the tires and put gas in your car," Parr says. "If a car had the miles the A/C in your house had, most cars would have a million miles on them.