Leaving for the Season? Here’s How to Set Your AC Before You Go

If you split your time between Florida and somewhere up north, you already know the drill: close up the house, stop the mail, and head out before hurricane season or the next heat wave. But one mistake seasonal residents make over and over is either turning the AC off completely or leaving it running on autopilot — both of which can lead to expensive problems waiting for you when you return.

Never Turn the AC Off Completely

It’s tempting to shut the system off entirely to save on electricity while you’re away, but in Florida, that’s one of the most common and costly mistakes a seasonal homeowner can make. Without air conditioning running, indoor humidity climbs quickly in a closed-up house — often well above the 60% threshold where mold and mildew start to grow on walls, furniture, cabinets, and clothing. By the time you return, you may be dealing with a mold remediation bill far larger than months of electricity would have cost.

The Right Thermostat Setting for a Vacant Home

Instead of turning the system off, set your thermostat to a “vacation mode” temperature — typically 80–82°F. This keeps the system running just enough to control humidity without the expense of cooling an empty house to everyday comfort levels. If your thermostat has a separate humidity control (many smart and some standard thermostats do), set it to maintain indoor humidity around 50–55%, which is the real target for preventing mold growth, not just temperature.

Consider a Smart Thermostat Before You Leave

If you don’t already have one, a smart thermostat is one of the most useful upgrades for a seasonal Florida home. It lets you check in remotely, adjust the setpoint if a heat wave rolls through while you’re gone, and get alerts if the system stops running or humidity climbs out of range — catching a problem in week one instead of discovering it in month four.

Have the System Serviced Before You Leave, Not After You Return

A system that’s about to fail is far more likely to do it under the extra strain of running continuously, unattended, for weeks or months. A pre-departure tune-up — checking refrigerant levels, cleaning the coil, testing capacitors and the contactor, and clearing the condensate drain line — catches the kind of small issues that turn into a full system failure (and a flooded closet) while no one’s home to notice.

Clear the Condensate Drain Line

A clogged condensate drain is one of the top causes of water damage in vacant Florida homes. Algae and debris build up in the drain line over time, and when it finally blocks completely, the overflow pan fills and water backs up into the house — sometimes for weeks before anyone finds it. Have this line cleared and, if your system doesn’t already have one, ask about installing a float switch that automatically shuts the system down if the drain backs up.

Arrange for Someone to Check In

Even with a smart thermostat and a pre-departure tune-up, it’s worth having a neighbor, property manager, or home-watch service physically check the house periodically. A thermostat can tell you the temperature is holding, but it can’t tell you a water leak started elsewhere in the house, or that a breaker tripped and the whole system is off.

A Quick Pre-Departure Checklist

• Schedule a tune-up 1–2 weeks before you leave, not the day before.
• Set the thermostat to 80–82°F, or your humidity-control setting if your system supports it.
• Clear the condensate drain line and confirm there’s no existing clog.
• Replace the air filter so it isn’t working against reduced airflow for months.
• Arrange a check-in with a neighbor, property manager, or home-watch service.

Frequently Asked Questions

Is it cheaper to just turn the AC off while I’m away?
It may look cheaper on your electric bill, but the risk of mold damage, swollen cabinetry, and musty odors from months of uncontrolled humidity almost always costs far more than running the system at a higher setpoint.

What temperature should I leave my AC at for a few months away?
Most HVAC technicians recommend 80–82°F for Florida homes left vacant for extended periods — low enough to control humidity, high enough to limit energy use.

Should I shut off the water heater and other systems too while I’m away?
That’s a good idea for other systems, but the AC should stay running at a vacation setpoint rather than being shut off completely — it’s doing an important job even when no one’s home.

Heading out for the season? Schedule a pre-departure AC tune-up with Bayside Heating & Air Conditioning before you go — call (727) 669-4300.