Florida is not as tough on air conditioning as many people think. In fact, a properly-sized, well-maintained system will last 20-years or more. When it comes to sizing, bigger is not better. An oversized system will be noisy, windy, and create a situation that cools the area quickly but without dehumidification, and any Floridian knows that humidity is equally important as temperature. To make matters worse, an oversized system will short-cycle. That means it’ll start, run for a short period, stop, then repeat a few minutes later. Electric motors experience the greatest stress upon startup, and the more startups they endure, the faster their components will wear out. It’s better for the system to run for longer periods and have longer downtime between cycles.

Old school rule-of-thumb sizing doesn’t apply with today’s high efficiency building methods. Be sure your system is properly sized by asking your contractor to conduct a heat load analysis, and resist the urge to go a “half-ton more”.

Modern thermostats tout the ability to control temperature differentials to within a half-degree. Great for comfort, but bad for equipment as it forces short cycles. The larger the differential, the longer the system will cycle. Set yours to at least 1.5°.

It’s an air conditioner, not a refrigerator! Did you know most air conditioning manufacturers design the equipment to cool approximately 20° below outdoor temperature? That means on a 98-degree day you should have your thermostat set at 78. Speaking of thermostats, everyone knows setting the temperature lower will make the system cool faster, right? Well, unless you’ve got a high-tech variable capacity or multi-stage system (and you’d know if you did!) that’s not the case. A thermostat is not a dimmer switch; it’s an on/off switch. I’ve seen thermostats set at 70° on hot days. What happens next is pretty typical; the system, overburdened by delayed maintenance, starts to freeze and loses capacity. The room temperature rises, so the occupant does the only sensible thing; he buries the thermostat at 60°. The evaporator coil becomes encapsulated in ice causing airflow to diminish. The home temperature now rises quickly and a service call is placed. $150+ later, the system has thawed, the dirty filter has been replaced, and the house is cool again. The takeaway? Keep your filters clean and your thermostat setting within reason.

Your condensing unit (the outdoor section of a split system) has a tough life. It needs to work in extreme heat and driving rain, gets covered in grass clippings and dirt from leaf blowers, and usually has garbage cans stacked next to it, not to mention the gigantic, overgrown boxwood which is completely obscuring it. Like I said, a tough life. Make its life easier by establishing a no-fly zone at least a foot around it in all directions, and don’t cover it. With anything. Ever. It’s made to be outside. Covering it only makes it an enticing home for reptiles and rodents. Keep it clean by spraying the exterior coils with water vigorously at a downward angle. No need to cut the power; it’s made to get wet. Don’t use brushes or chemicals. Just water. Want a pro tip? Replace the compressor and fan motor run capacitors every 5 years. The motors will run cooler, quieter, and longer.

If you're not inclined to do your own maintenance, get a service agreement with a reputable local contractor. They'll automatically schedule maintenance for you, and it's in their best interest to catch problems before they cause failures. Besides, I know firsthand that contracted customers get preferred appointments during a heatwave.

No, not all techs are salesmen. But plenty of techs are incompetent and lazy. Sure, the contractor I worked for threw us a bone for recommending replacement systems, but I got a greater reward by getting a broken system running. There were plenty of times I was called out for a second opinion on a condemned system to find an easy fix that the previous guy was too lazy to look for, or just didn't know what he was looking at. You get what you pay for in this industry, so stay far away from the coupon guys who offer $49 tune-up specials. Stay with the local guy who has been in business for 20+ years and lives amongst his customers.