Reopening a Boca Raton Home After a Summer Away: An AC Start-Up Checklist

Plenty of neighbors are doing the same thing this month. Census data counts 4,679 of Boca Raton's 49,128 housing units as seasonal, recreational or occasional-use homes, and 68,613 of 719,463 across Palm Beach County ^[2]. By our arithmetic that is about 9.5 percent of homes in both the city and the county.

Those homes sat through a humid summer. A 2005 Florida Solar Energy Center study of vacant homes reported that "outdoor RH averages about 77% from June through October" ^[3]. The season is turning, but it has not turned yet: the normal high at Palm Beach International Airport is still 87 degrees on October 1 and 82 on October 31 ^[4].

Most seasonal-home advice covers the day you leave. This AC start-up checklist covers the hour you get back. It is also honest about something other guides skip: two official Florida sources disagree on what the AC should have been set to while you were gone.

Key takeaways

• Read the humidity before you change anything. A reading above 60 percent is above the EPA's guidance ^[1].
• Two official sources disagree on the away setting, so check how your own home held up instead of trusting one number.
• Six checks, done in order, need no tools and no open panels.
• Standing water at the air handler ends the checklist. Turn the system off and call.
• Call or text Direct Cooling at (561) 210-7605 to book a start-up visit.

Read the Humidity Before You Touch the Thermostat

Relative humidity is the amount of water vapor in the air compared with the most the air can hold at that temperature. It is the first thing to read in a home that has been closed for months, because it shows how the house held up while you were away. A reading above 60 percent means the home is damper than the EPA's guidance.

The EPA's guidance is direct: "If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity." ^[1] A small digital humidity gauge, called a hygrometer, gives you the number in a minute.

Take the humidity reading in a Boca Raton home before you lower the thermostat, because cooling the air changes the reading. Check two places: the main living area, and a closed closet or interior bathroom where air moves least. Write both numbers down. If the closet reads much higher than the living area, moisture has been sitting in the still parts of the house.

The Florida Solar Energy Center's 2005 report explains why the number matters: "Mold and mildew grow when RH is high, say over 70%, for extended periods of time." ^[3] A musty smell on the first day back is a reason to look closer. It is not proof of mold. The humidity number tells you more than the smell does. For more on how an air conditioner controls moisture, see our guide to how your AC controls humidity.

What the Away Setting Should Have Done

The away setting has one job: run the air conditioner often enough to pull moisture out of an empty home. The published advice on how to do that does not agree. Florida Power & Light gives a temperature range and a humidity target, the University of Florida gives a ceiling of 85 degrees, and Florida research found that 85 degrees ran too little in the homes it tested.

Read the third row with its limits. The Florida Solar Energy Center monitored three homes in Brevard County, and the report is more than 20 years old ^[3]. Three homes cannot settle the question for a Boca Raton condo. They do show that a thermostat number alone does not guarantee a dry house.

That is why the humidity reading comes first. Your home just ran a months-long test of its own setting. If the reading is under 60 percent, the setting worked. If it is higher, the setting, the humidistat or the equipment needs attention. UF/IFAS adds one instruction worth following either way: "Have the humidistat calibrated by your air conditioning company." ^[6]

Community rules can shape the setting too. Our pages on AC repair in Century Village and AC repair in Kings Point each cover closing up a condo for the summer. Our page on AC repair in Boca West explains how the equipment is laid out in its mid-rise buildings.

Want a licensed technician to do the start-up check? Call or text Direct Cooling at (561) 210-7605, or see what an AC maintenance visit covers.

The Six-Step AC Start-Up, in Order

An AC start-up sequence is a short set of checks done in a fixed order, from the least disruptive to the most, before a home's cooling goes back to everyday use. The six steps below need no tools and no open panels. Each one comes from published guidance. The order is ours: it is not a manufacturer procedure, and it stops the moment you find water.

1. Read the humidity. Take the two readings described above before you change any setting. The EPA's line is 60 percent ^[1].
2. Check the air filter. ENERGY STAR's maintenance checklist says: "Inspect, clean, or change air filters once a month in your central air conditioner, furnace, and/or heat pump." ^[7] A Department of Energy infographic from 2014 adds that routinely replacing or cleaning filters can lower an air conditioner's energy use by 5 to 15 percent ^[8].
3. Look at the drain pan and drain line. Find the pan under the indoor unit and look for standing water, rust or stains. Look, don't dismantle. If there is water in the pan, stop here.
4. Walk around the outdoor unit. With the system off at the thermostat, clear leaves, palm fronds and anything leaning against the cabinet. Don't open the cabinet or reach inside.
5. Lower the thermostat once, with the fan on Auto. Set the temperature you live at in one step. Florida Power & Light suggests 75 to 78 degrees when you are home, and notes that switching the fan from Auto to On can add more than 200 extra hours of fan run time each month ^[9].
6. Listen through one full cycle. Stay home while the system starts, runs and shuts off. You want cool air at the vents, a steady outdoor unit and no new water.

After a day of normal running, take the humidity reading again. If a Boca Raton home that started above 60 percent is not coming down, that is a finding, and it belongs in a service call.

What the Drain Line Tells You After Months of Light Use

The condensate drain line carries away the water an air conditioner pulls out of the air. Trane notes that a drain line can clog with mold and mildew that form in standing water in the drain pan ^[10]. In a home that sat empty, nobody was there to notice. That makes the drain area worth a careful look on the day you return.

ENERGY STAR puts the risk in one sentence: "A plugged drain can cause water damage in the house and affect indoor humidity levels." ^[7] A slow drain can also explain a high humidity reading, because water that cannot leave the air handler stays in the home.

Where an overflow could damage the building, Florida's mechanical code requires one of four protections for a cooling coil. One of them is a water-level detection device "that will shut off the equipment served in the event that the primary drain is blocked." ^[11] That device is commonly called a float switch. If your air conditioner was off when you walked in and the thermostat is still calling for cooling, a tripped float switch is a possible reason.

Time matters once water is out of the pan. The EPA's guidance: "It is important to dry water-damaged areas and items within 24-48 hours to prevent mold growth." ^[1] A stained ceiling or a wet closet floor under the air handler is not a wait-and-see item.

When the Checklist Ends and a Service Call Starts

The checklist ends when a check turns up something you cannot see the cause of. Call a licensed air conditioning contractor if you find standing water, a breaker that will not stay on, ice on the indoor unit, an outdoor unit that hums without starting, a smell that is still there after a day, or humidity that stays above 60 percent after a day of normal running.

A start-up visit from a technician covers what a homeowner cannot safely reach. ENERGY STAR's checklist for a professional visit includes checking the condensate drain, cleaning the evaporator and condenser coils, and checking the refrigerant level ^[7]. Refrigerant and electrical work are not do-it-yourself jobs.

What a visit costs depends on what it finds. A system that only needs a filter, a cleared drain and a set of readings is a maintenance visit. Water damage, a failed part or a refrigerant leak turns it into a repair, and the size of that repair depends on the part, the access and how long the problem ran. Ask for the readings in writing either way, so next October you have a baseline.

The weather is easing. Normal highs at Palm Beach International fall from 82 degrees on November 1 to 78 by November 30 ^[4], which makes the weeks after you return a comfortable time to have work done. Direct Cooling is a Florida Certified Air Conditioning Contractor, license CAC1819111. Our maintenance plan includes two tune-ups a year, which a seasonal owner can time for the month of return and the month of departure.

Call or text (561) 210-7605 to book a start-up visit in Boca Raton.

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Is 60% humidity high for Florida?What should your AC be set at in Florida?

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Is 60% humidity high for Florida?

Indoors, yes. The EPA's guidance is to keep indoor relative humidity below 60 percent, ideally between 30 and 50. Outdoor air in Florida runs far higher, which is normal. The number that matters for a Boca Raton home is the indoor reading, taken before you change the thermostat, in both a living area and a closed closet.

What should your AC be set at in Florida?

Florida Power & Light suggests 75 to 78 degrees when you are home and around 82 degrees when you are away. For months away, the published advice ranges from 78 to 85 degrees depending on the source. The more useful test is the result: an indoor humidity reading under 60 percent when you come back means your setting worked for your home.