What Florida's Climate Does to Commercial AC

If you run a restaurant, salon or small shop in Florida, your AC probably works harder than the same unit would in most other states. That doesn't mean it has to keep breaking. Most of the damage builds up slowly, and most of it can be slowed down with the right maintenance.

The cooling season barely stops

The National Weather Service office in Miami puts the median start of South Florida's summer season at May 21 and the median end at October 17. During those months, daily highs average in the upper 80s and lows rarely drop below 70. So there isn't much of a cool break overnight, and the AC carries the building for most of the year.

Carrier's service manual for its air conditioners says how often maintenance is needed depends on hours of operation, geographic location and local conditions. In Florida, all of those point toward more frequent service than a once-a-year check.

Humid air means more water to deal with

An air conditioner does two jobs. It lowers the temperature, and it pulls moisture out of the air. Research from the Florida Solar Energy Center describes the cooling load as both: the temperature part and the moisture part. In Florida's climate the unit is removing moisture for most of the year.

That water runs out through the condensate drain. A Palm Bay contractor, Inlet Mechanical, points out that in a Florida cooling season the drain runs wet almost all year, so the slime that grows inside never dries out. When the drain clogs, ENERGY STAR notes it can cause water damage and affect indoor humidity.

Many systems have a float switch that turns the AC off when water backs up. That protects your ceiling, but to you it looks like the AC just quit. If the unit stops and there's water around the indoor unit or drain pan, mention the drain when you call. If the room feels damp even when the AC is running, our post on a dining room that feels humid and muggy covers the other causes.

Salt air corrodes condenser coils

Carrier treats anything within 2 miles of the ocean as a coastal environment. Its manual says salt water can travel that far as sea spray, mist or fog, and that how bad the corrosion gets depends on things like line of sight to the water, wind direction, humidity and how often the coil goes from wet to dry. Salt sticks to the aluminum fins and can cause the coil to fail early.

Trane says the same in its coil-coating literature for packaged rooftop units: airborne salts in coastal areas shorten the life of air-cooled coils.

What you can do depends on whether you're replacing a unit or keeping the one you have.

• When replacing. Ask about coastal models or factory-coated coils. Carrier's coastal units have epoxy-coated coils, baked-on paint on the sheet metal and coated screws. Trane offers a factory epoxy coating on its rooftop units that covers the whole coil, including the fin edges.
• Coatings added later. Trane notes that coatings sprayed on in the field mostly protect the surfaces you can see, and the inner fins corrode at the uncoated rate. Worth knowing before you pay for one.
• Keeping the coil clean. Carrier's guidance for coastal sites is to inspect the coil and the base pan often, especially after storms and high winds, and to flush the coil as often as inspection shows it's needed. It also warns against high-pressure water, because damaged fins can lead to higher operating costs or compressor damage.

Lightning and power surges

The National Weather Service calls Florida the lightning capital of the United States. In South Florida, afternoon thunderstorms are close to a daily event during the rainy season.

FPL says lightning can cause brief surges in the power supply, usually under a second long. Its business surge program says one surge can damage equipment your business depends on, and lists air conditioning among the equipment it covers. FPL recommends two things for AC:

• Surge protection on the inside and outside of the building, with both giving the best protection.
• A time-delay relay if your unit doesn't already have one. It stops the unit from restarting for about three to five minutes after the power flickers, which reduces the chance of damaging the compressor.

Ask your AC company whether your unit has both. If the breaker for the AC starts tripping after storms, read our post on an AC that keeps tripping the breaker before you reset it again.

Storms and flooding

Ready.gov's flood guidance says not to touch electrical equipment if it's wet or if you're standing in water, and to turn off the power if it's safe to do so. If water reached the outdoor unit, keep it off and have someone check it before it runs again. After any big storm, Carrier's advice to inspect the coil and base pan applies too.

Where to look first

Based on the above, these are the parts most exposed to Florida conditions:

• The outdoor coil. Salt, dirt and storm debris. ENERGY STAR says dirty coils make the system run longer and shorten the life of the equipment.
• The condensate drain. Clogs from year-round moisture, which can shut the unit off through the float switch.
• The compressor and electrical parts. Exposed to surges. ENERGY STAR also says loose electrical connections can make a system unsafe and shorten the life of major components.

A basic maintenance routine

None of this is complicated. Most of it is the standard ENERGY STAR checklist, done more often because of where you are. If you look after several sites, our commercial HVAC maintenance schedule sets out each task by how often it's due.

• Check the filter every month and change it when it's dirty.
• Have a technician service the unit at least once a year, before the hot season. Ask them to clean the indoor and outdoor coils, check the condensate drain, tighten electrical connections and check the refrigerant level. These are all on the ENERGY STAR list.
• If you're near the coast, have the coil and base pan checked more often, and after storms.
• Ask about surge protection and a time-delay relay.
• Write down when problems happen and what you noticed. It helps the technician find the cause faster. Our guide on what to tell your HVAC company when you call has a short list.

Early signs worth acting on

A unit usually gives some warning before it stops. Watch for:

• Air from the vents that isn't as cold as it used to be, especially in the afternoon. Our post on an AC blowing warm during service explains why it often shows up at the busiest hour first.
• The unit running longer than it used to, or not shutting off on hot days.
• Water around the indoor unit, or the AC shutting off for no clear reason.
• The breaker tripping, especially after a storm.

Calling when you first notice one of these usually means a normal visit at a time that suits you. Waiting until the unit stops usually means whoever can come today, at their rate.

Where monitoring fits

The hard part is noticing those signs early. Most owners don't have time to keep an eye on the AC, and on a busy day a few degrees warmer is easy to miss.

SmartHVAC is a small sensor that goes on the AC unit you already have. It measures the air going in and coming out, and how hard the unit is working. If the air coming out is a few degrees warmer than usual, or the unit is running longer than it used to, you get an alert on your phone and by email. The alert says what we see, what it's likely to be, and whether it can wait for a normal visit. Then you call whoever you normally call. It doesn't fix anything, and you keep your AC company.

To see how it would work on your units, book a demo.