Every October, Palm Beach County starts filling back up. License plates from New York, New Jersey, Ontario, and Michigan reappear in driveways from Jupiter down to Boca Raton, and thousands of seasonal residents walk into homes that have been sitting closed for six months.
Some of those homeowners walk into exactly what they left: a cool, dry, comfortable house.
Others open the door and get hit with it — that musty smell. Damp air. Maybe spots on the ceiling or a warped cabinet door. And somewhere in the middle of it all, an air conditioner that’s been quietly struggling (or sitting off entirely) since April.
The difference between those two homecomings almost always comes down to how the AC was set up before the owners left — and whether anyone checked on it along the way.
Whether you’re arriving for the season or planning ahead for next spring’s departure, here’s the checklist we recommend to seasonal residents across Palm Beach County.
Why Vacant Florida Homes Are Different
In most of the country, you can shut a house down for six months and come back to dust. In South Florida, you come back to whatever six months of heat and humidity decided to do with the place.
An empty home here isn’t really empty. It’s a sealed box sitting in 90°F heat and 80-plus percent humidity, with no one opening doors, running fans, or noticing problems. Without active humidity control:
- Mold and mildew can take hold on walls, furniture, and inside closets
- Wood floors and cabinetry absorb moisture and warp
- Drywall and paint bubble and stain
- The AC drain line clogs with algae while nobody’s watching, and a float switch shutoff means no cooling at all for months (see our guide on signs your AC drain line is clogged)
And the one appliance standing between your home and all of that is the air conditioner you’re about to leave unattended.
Arriving for the Season? Start Here
Before you settle in, give the system ten minutes of attention.
1. Replace the Air Filter
Even in a vacant home, the filter has been collecting dust every time the system ran. Start the season with a fresh one.
2. Look (and Smell) Before You Blast It
Walk the house with the AC running. A musty smell from the vents, weak airflow in certain rooms, or moisture around the air handler are all worth addressing now — not in December when the house is full of family.
3. Check Around the Indoor Unit and Drain Line
Look for water stains, rust in the drain pan area, or standing water. Six months of algae growth in the drain line is one of the most common things we find in snowbird homes each fall.
4. Inspect the Outdoor Unit
Hurricane season isn’t over until November 30. Clear away leaves, mulch, and anything that’s grown or blown in around the condenser over the summer. If you’re near the coast, look for corrosion on the coil and cabinet — salt air doesn’t take the summer off (here’s how salt air affects AC units in coastal Palm Beach County).
5. Book Your Seasonal Tune-Up Early
Schedule a professional maintenance visit at the start of the season, not when something breaks in January. A fall tune-up catches what summer did to the system — and October and November appointments are much easier to get than ones in the weeks around the holidays.
Leaving for the Summer? Set the House Up Right
This is where most of the damage gets decided. The single biggest mistake seasonal residents make is turning the AC off completely to save money. In Florida, that’s not savings — that’s a bet against humidity, and humidity usually wins.
1. Don’t Turn It Off — Turn It Up
Leave the AC running with the thermostat set around 77–80°F. The goal while you’re gone isn’t comfort — it’s moisture removal. A system cycling at 78°F keeps humidity in check for a fraction of what you’d pay cooling to 72°F, and far less than what mold remediation costs.
2. Better: Use a Humidistat or Smart Thermostat
A humidistat paired with your thermostat runs the AC based on moisture, not temperature — the right tool for a vacant Florida home. A smart thermostat does even more: you (or a neighbor, or your AC company) can see from anywhere that the system is alive and the humidity is under control. If the system goes down in July, you find out in July, not when you open the door in October. We can set either up as part of a service visit.
3. Have the Drain Line Cleaned Before You Go
A spring drain line flush is cheap insurance. If the line clogs mid-summer with nobody home, the float switch shuts the system off — and your home sits unprotected for months.
4. Help the Air Move
Leave interior doors and closet doors open so conditioned air reaches everywhere. Closed-up closets and rooms are where mold shows up first.
5. Arrange a Check-In
A neighbor, property watcher, or family member who walks through monthly — and knows what a warm, humid house means — is worth a lot. Ask them to confirm the AC is running and nothing smells off.
6. Get a Pre-Departure Inspection
If the system is going to fail, it’s better to know in April than to find out in October. A spring tune-up before you leave covers the refrigerant, electrical components, coil condition, and drain line — the full rundown is in our Florida HVAC maintenance checklist.
A Note on Older Systems in Seasonal Homes
Many seasonal properties in Palm Beach County — especially condos in communities that date back decades — are running systems well past the ten-year mark. An aging AC in a full-time home gives you warning signs you notice day to day. In a seasonal home, it fails silently with nobody there.
If your system is old enough that you’re crossing your fingers each spring, it’s worth reading up on when it’s the right time to replace an AC system in Florida — and fall is one of the best times of year to do it, before the spring rush.
Conclusion
A Florida home does fine on its own for six months — as long as the air conditioner is set up to protect it and someone can tell if it stops.
Set the thermostat for humidity, not comfort. Clean the drain line before you leave. Get a tune-up at the start and end of each season. And consider a smart thermostat so the house can tell you when something’s wrong.
Southern Mechanical Services works with seasonal residents throughout Palm Beach and Martin County — pre-departure inspections, arrival tune-ups, drain line service, and smart thermostat setups for homes that sit empty part of the year. If you’ve just arrived for the season or you’re planning ahead, give us a call at (561) 907-6030 or schedule service online.
