What Temperature Should You Leave Your Florida House at in Summer?

What temperature should you leave a Florida house at in summer?

There is no single number every authority agrees on, but there is a clear ceiling and a clear goal. UF/IFAS Extension says there is no reason to keep an empty home cool, but the AC should run periodically to remove moisture, and it should be set no higher than 85°F. Above that, the publication warns, indoor humidity can climb past 55 to 60%, which is enough to grow mold and bacteria.

Florida Power & Light's snowbird tips, reported by WGCU in April 2026, give two options depending on your thermostat:

Your setup	Suggested setting	Source
Programmable or smart thermostat	72°F for two hours before sunrise, then 88°F the rest of the day	FPL
Basic, non-programmable thermostat	80°F, keeping indoor humidity under 60%	FPL
Any system	No higher than 85°F so the AC cycles on and off	UF/IFAS

Pick the row that matches your equipment, then confirm it with a humidity reading. The number on the thermostat is only a means to that end.

Why humidity matters more than the temperature

Your air conditioner removes moisture only while the compressor is running. Set it high in an empty house and it may barely run on a mild, muggy day, so the air stays damp even though the temperature looks fine. That is how owners in Lely or on Marco Island come back in October to a home that was never hot but still smells musty.

The Florida Solar Energy Center studied exactly this in vacant homes. Setting the AC at 85°F did not give acceptable humidity control, mainly because the system did not run long enough. Running it at about 74°F for two hours, for example from 3 to 5 a.m., kept relative humidity below 65% most of the time in most homes. FSEC treats 70% as the critical level above which mold growth is likely. The full FSEC report also recommends leaving the fan on auto so moisture pulled off the coil isn't blown back into the house.

That early-morning run is the logic behind FPL's 72°F-then-88°F program: a short, hard run when the house is coolest pulls water out, and the high setting the rest of the day keeps energy use down.

What humidity level should a closed-up house stay below?

Aim to keep indoor relative humidity below 60%. The EPA recommends below 60% and ideally between 30 and 50%, and FPL uses the same 60% line for vacant Florida homes. A summer reading in the low to mid 50s gives you a margin for a stormy week.

Readings that point to a problem:

• Humidity above 60% on more than an occasional visit
• Condensation on windows, sliders, vents or the air handler
• A musty smell in closets, bathrooms or the laundry room
• Temperature sitting well above the set point, which can mean the AC isn't cooling at all

Any of these is a reason to call your HVAC company, not to wait for the next visit.

Do you need a humidistat, a smart thermostat or a dehumidifier?

A thermostat with a humidity display or dehumidify setting makes this much easier, because you can see the result instead of guessing. If your system has a humidistat, UF/IFAS advises having your AC company calibrate it before you leave. FSEC found that the built-in humidistats on the portable dehumidifiers it tested were erratic, and that running the dehumidifier on a timer was more dependable.

If your system can't control humidity, FPL suggests dehumidifiers set to about 58%, placed near sinks and showers, roughly one per 1,000 square feet. UF/IFAS adds that a dehumidifier should sit centrally with a continuous drain, because a full bucket stops it within days. Our guide to dehumidifiers and humidistats for Florida homes covers equipment choices in more detail.

Why turning the AC off is a mistake

Some owners shut the AC off to save on the electric bill. In a Gulf Coast summer that trade rarely works out. FSEC found that letting a vacant house float with no cooling left average humidity near 70%, which it called marginal at best. Mildew on upholstery, leather, closet walls and grout costs far more to deal with than the electricity you saved.

Two other settings help the AC do its job:

• Leave interior doors open, including closets where possible, so air reaches every room. Both UF/IFAS and FSEC recommend it.
• Turn ceiling fans off. They move air but don't remove moisture, and UF/IFAS lists them on the day-you-leave checklist.

For the rest of the prep, see how to prevent mold in a closed-up Florida house.

How to set it up before you leave

1. Three weeks out: book an AC service. UF/IFAS lists cleaning the coil and blower, checking refrigerant, and cleaning the condensate pan and drain line. Change the filter yourself.
2. Two weeks out: program the summer setting while you're still in the house. You'll see within days whether the humidity holds below 60%.
3. One week out: test any dehumidifier and confirm its drain line runs to a drain.
4. The day you leave: check the AC settings one last time, write them down and photograph the thermostat.

I tell owners to leave that photo with whoever checks the house, so a changed setting is obvious at a glance. The room-by-room steps are in our summer closing checklist.

How to know the setting is working while you're away

A Wi-Fi thermostat or a simple remote temperature and humidity sensor can alert your phone when readings drift. FPL's online Energy Manager tool also flags unusual energy use, which can be the first sign an AC has stopped running or is running nonstop.

Sensors can't see a clogged condensate line, a wet ceiling or mildew starting in a closet, though. That's why our home watch reporters record the thermostat temperature and indoor humidity on every visit, alongside photos, and report problems right away with a recommendation. Read how often home watch should visit for scheduling, and when you're ready, our seasonal closing cleans leave the settings recorded on the way out.