What fifty-two check-ins a year do to an air conditioner, and the calendar that keeps up

The rental year, in seasons

Late February to April: spring break and the pollen. The first wave of guests arrives as the oaks and pines drop pollen on every outdoor coil in the county. Systems that sat idle or ran lightly through the winter come up to full duty in a week. This is when a coil that was not cleaned last fall shows itself as “the AC isn’t keeping up,” and when the first drain lines clog.

May to August: full occupancy, full humidity. Every Saturday, a new set of guests, a new thermostat setting, a new pattern of doors left open. Dew points sit in the seventies. The system runs nearly continuously, the filter loads fast, and the drain line is doing more work than at any other time of year. This is the season that breaks rentals.

September and October: the storms and the lull. Occupancy dips, tropical weather threatens, and systems that ran flat-out all summer finally get a break they should have had in April. It is the best window for the second maintenance visit.

November to January: Nights of Lights and the frost nights. Downtown St. Augustine fills again for the holiday lights, from the Bridge of Lions up St. George Street, and the beach rentals book up behind it. The heat pump runs in reverse for the first time since March; strips kick in on the handful of frost nights. A system that has never been checked in heating mode finds out now, with a full house.

What turnover does that a family doesn’t

A family home has someone who notices the sound change, smells the must, sees the water on the closet floor the day it starts. A rental has a cleaner for three hours on Saturday and a guest who will not report anything short of no cool air at all. Four problems grow in that gap.

Frozen coils. Guests set the thermostat very low and open the sliders to the breeze. Warm, wet air across a cold coil freezes it; airflow stops; the ice melts into the closet. One weekend, one insurance conversation.

Drain lines. With the system running constantly in humid air, biological growth in the drain line builds faster than anywhere else. Without a working float switch, the overflow finds the ceiling below or the closet floor.

Filters. Sand tracked in, sunscreen aerosol, a houseful of people and pets, and nobody whose job it is to look at the filter. A loaded filter raises static pressure, freezes coils and runs up the bill.

The outdoor unit. Nobody rinses it. At a Vilano Beach or Crescent Beach rental that means a season of salt on the coil; under the Lincolnville or Lighthouse Park oaks it means a top full of leaves and acorns.

Set up a turnover program

The cleaner’s sheet

This is what we leave taped inside the air-handler closet, laminated, filter size written at the top. It takes a cleaning crew about five minutes on a turnover.

1. Thermostat. Set to the owner’s standard (we suggest the mid-seventies with the fan on auto). Note anything odd: a locked-out screen, a blank display, a reading that doesn’t match how the house feels.
2. Filter. Check the date written on the frame. Replace if it has been a month, or sooner if it is grey. Spares in the closet.
3. Closet floor and pan. Dry? Any standing water in the drain pan under the unit? Any rust streaks or a musty smell when the door opens?
4. Drain cleanout. Cap on the drain line’s access tee. If the owner has approved it, a cup of distilled vinegar down the line.
5. Outdoor unit. Top clear of leaves and debris. No shrubs grown into the sides. Nothing stored against it.
6. Report. Text the manager a photo of anything on this list that isn’t right. That text is how a Friday-night breakdown becomes a Tuesday-morning repair.

The owner’s quarterly list

The cleaner catches what is visible. The owner or manager covers what needs a calendar.

• Quarterly: confirm the smart thermostat is online and its limits are still set; review the energy use trend if the thermostat reports it. A step change with no occupancy change is a system asking for attention.
• Twice a year: a professional maintenance visit, timed to the start of the season in March and the lull in September or October. Charge, coil cleaning, drain line and float switch, electrical components, heating mode in the fall.
• Annually: rinse the outdoor coil after the pollen; check the condensate line’s exit for a clear path; look at the age of the system and decide what the plan is before it decides for you.
• At every refurbishment: if walls are open or ceilings are down, that is the moment to fix duct and return problems that have been making the upstairs bedroom the one guests complain about.

Equipment choices that suit a rental

Some upgrades pay for themselves faster in a rental than in a home. A thermostat with remote access and settable limits ends the 62-degrees-with-the-doors-open problem. A float switch that actually cuts the system off, tested, saves a ceiling. A whole-house dehumidifier keeps the house dry at a higher thermostat setting, which guests tolerate better than they admit and the bill rewards. On the beach, a coated outdoor coil adds years in the salt. And a maintenance agreement puts a rental ahead of the line on the Saturday in July when every system in St. Johns County is working.

When it breaks anyway

It will, eventually, on a Friday night with guests arriving. The call goes to a dispatcher who answers at that hour, the technician knows the property from the maintenance visits, the lockbox code is in the file, and the Friday-night invoice reads like a Tuesday one. That is the part of the plan that cannot be laminated.