DID YOU KNOW: If you have a service contract, you can place a service call online here.

(954) 900-6767

Call for Quote

(954) 900-6767

What’s the Best Thermostat Setting for Summer in Florida?

July 26, 2026
AC Systems & HVAC
19 min read

The U.S. Department of Energy says setting your thermostat to 78°F when you’re home versus 72°F saves 6% to 18% on your cooling bill. But in a Florida summer, the actual “ideal” setting is less about hitting a magic degree and more about not letting your house get sticky enough to potentially grow mold (and to make you miserably uncomfortable). The Florida summer thermostat setting that saves you money without wrecking your AC is a smaller window than most homeowners realize.

Real-world caveat first: if you’re a Florida homeowner, you probably don’t run your house at 78°F. Most of the Southeast Florida homeowners we work with sit closer to 72°F to 74°F while home, and honestly, that’s fine as long as humidity stays managed. You’ll pay more on the electric bill than the DOE savings-max path would cost you, but you won’t create the humidity or wear problems that come from swinging your thermostat all over the place.

Here’s what the research actually shows, why the popular “let it drift up all day and cool it down at night” trick doesn’t work as well in Southeast Florida as it does in Denver or Boston, and how to think about the tradeoff between comfort and savings.

The Short Answer for a Florida Home

  • When you’re home and awake: 72°F to 74°F is where most Southeast Florida homeowners actually land for comfort. 76°F to 78°F is the DOE savings-max range if you’re prioritizing the electric bill over comfort.
  • When you’re asleep: 70°F to 73°F (where most South Florida homeowners actually land, and closer to the sleep-research ideal)
  • When you’re away for the day: 76°F to 78°F (do not go higher than 82°F under any circumstances)
  • When you’re on vacation for more than a week: 80°F to 82°F with humidity control active
  • Indoor humidity target: below 60%, ideally 45% to 55%

The cap of 82°F while away is where Florida homeowners get in trouble. Anything higher than that lets indoor humidity climb into the range where mold may get comfortable and where the AC has to run a long, hard recovery cycle when you get home. More on why below.

What the Department of Energy Officially Recommends

DOE’s Energy Saver program has been publishing the same core cooling guidance for years: 78°F when you’re home, higher when you’re away or asleep. Their published range says raising your thermostat from 72°F to 78°F cuts cooling costs by 6% to 18% (DOE, Top 11 Things You Didn’t Know About Saving Energy at Home: Summer Edition).

ENERGY STAR pushes the number a little further: pair a 2°F thermostat setback with a ceiling fan and you can save up to 14% on cooling with equivalent comfort (ENERGY STAR).

Both agencies are quick to add a caveat that gets left out of most homeowner articles: EPA has said publicly (via the ENERGY STAR programmable thermostat program) that they are “not aware of any per-degree savings method that is well supported by research.” The 6% to 18% figure is climate-averaged. Your actual savings depend on your climate, your home’s tightness, your equipment, and how big a setback you use. In Florida, the top end of that range is very hard to hit.

Why Florida Is a Different Problem Than Most of the Country

In dry climates, cooling is almost pure temperature work. In humid climates like Southeast Florida, your AC is doing two jobs simultaneously: cooling the air (sensible load) and pulling water vapor out of it (latent load). Both are essential for comfort. Only one is what the thermostat measures.

Three facts from the building science research explain most of what happens next:

  • Your AC’s latent capacity is small. A conventional central AC is designed with roughly 20% to 25% of its total capacity dedicated to moisture removal at design conditions (Rudd 2013, Building Science Corporation, BA-1310). The rest is temperature work.
  • Your AC has to run for 10 to 15 minutes continuously before it starts pulling meaningful water off the evaporator coil (Straube 2011, BSD-022). Short cycles don’t dehumidify.
  • Your thermostat measures temperature, not humidity. As building scientist Armin Rudd put it, “conventional cooling systems have difficulty keeping humidity levels within comfortable and healthy limits” because “thermostats sense temperature and not humidity” (Rudd, Ueno, Lstiburek 2005, BA-0505).

Translation: your AC is a decent dehumidifier, but only when it’s running. When it shuts off, moisture keeps coming into your house through the walls, the ductwork, ventilation, cooking, showering, and every person breathing. If the AC is off for hours, humidity climbs.

Is It Really Bad to Turn the AC Way Up During the Day and Cool It Down at Night?

The honest, research-backed answer: small daily setback (2°F to 4°F) is fine and can save you money. Aggressive setback (8°F or more) in a Florida summer creates real problems, but they are humidity problems more than compressor problems. Here’s what actually happens:

The humidity problem with high thermostat setpoints in summer (in Florida)

While the AC is off or barely running during the day, indoor humidity rises. Efficient, tightly-built homes actually make this worse because they have “longer off-times, during which indoor moisture can build up” (Rudd 2013). By late afternoon, indoor relative humidity in a Florida home with a set-back-to-85°F thermostat can easily push past 60%.

EPA’s guidance is to keep indoor humidity below 60%, ideally between 30% and 50%, to prevent mold growth (EPA, A Brief Guide to Mold, Moisture and Your Home). ASHRAE’s Standard 55 comfort range tops out at 60%. So the “just let it drift” strategy can push your house into mold-friendly territory every day of the summer.

The “sensible-first” recovery problem

When you come home and the AC kicks on to cool the house from 85°F back to 76°F, it satisfies temperature before it satisfies humidity. Once the thermostat hits its setpoint, the AC shuts off, even if the indoor air is still at 65% RH. The result: the house is cool but sticky, and a full recovery of comfortable humidity can take hours of on-and-off cycling. That is the mechanism building science engineers call the “sensible-first” problem, and it is well documented (Rudd 2013).

The equipment strain question

This is where HVAC folk wisdom gets a little ahead of the evidence. Manufacturer engineering documentation is clear that each compressor start is the hardest moment for the unit. Carrier states plainly that starting a compressor “requires significantly more energy than keeping it running” and that repeated cycling “places immense strain on the compressor and fan motors” (Carrier Residential). Trane commercial guidance limits compressors to about 12 starts per hour for this reason. So the physics is not made up.

What is not well documented is a specific number, such as “aggressive setback in Florida shortens residential compressor life by X years.” The peer-reviewed field data on that specific question is thin. So we’ll say what the research supports: aggressive setback creates long, hard recovery run times and can cause more start/stop cycles than a stable setpoint would. That is engineering-plausible wear you would rather avoid, but the bigger, better-documented problem is the humidity.

Where the “setback saves money” claim does hold up in Florida

The Florida Solar Energy Center at UCF ran a long-term field study of smart thermostats in 30-plus Florida homes and measured an average 9.5% savings on combined heating and cooling from smart-thermostat setback in a hot-humid climate (Shields 2016, FSEC/UCF). Notably, savings had “significant variation among homeowners.” The takeaway: setback with a well-programmed smart thermostat does save Florida homeowners money. But the savings are on the modest end of the national range, not the aggressive 18% top end.

The Sweet-Spot Schedule for a Southeast Florida Home

Combining the DOE baseline with the Florida-specific research, this is a schedule that saves money without inviting a mold problem:

  • 7 a.m. to 9 a.m. (waking up): 72°F to 74°F
  • 9 a.m. to 5 p.m. (away): 76°F to 78°F (keeping the daytime setback around 4°F protects both humidity control and an easy recovery)
  • 5 p.m. to 10 p.m. (evening): 72°F to 74°F
  • 10 p.m. to 7 a.m. (sleeping): 70°F to 73°F

If you want to chase the maximum DOE savings, bump the home-and-awake number up to 76°F to 78°F and the away number up to 78°F to 80°F. Your bill will go down. Most Florida homeowners we know try this once, get uncomfortable within a week, and set it back to 72°F to 74°F, which is a totally reasonable choice.

A note on the 70°F to 73°F night setpoint. That’s a bigger swing from your daytime setpoint than the 4°F cap we put on daytime setback, and it’s a fair question why the same warning doesn’t apply here. Two reasons. First, while you’re asleep and the AC is actively cycling all night, humidity stays managed — the mold-risk window we warned about happens during long off-periods when nobody is home, not during active cooling.

Second, cooler sleep is well-supported by sleep research. The National Sleep Foundation’s recommended range for adults is 60°F to 67°F for optimal sleep, so 70°F to 73°F is closer to that ideal without turning the bedroom into an ice box (Sleep Foundation, Best Temperature for Sleep). You will pay more on the electric bill for running cooler at night, but you are not creating the humidity or short-cycling problems that aggressive daytime setback causes.

If your house feels sticky at these settings, the fix is not to drop the thermostat lower. It’s to figure out why humidity is winning: undersized system, oversized system that short cycles, leaky ductwork in the attic, air leaks through windows/vents/doors (balcony doors are a big culprit here), or a return-air imbalance.

Do Smart Thermostats Fix This?

Partly. Smart thermostats (Nest, Ecobee, Honeywell) can save the average Florida household around 9.5% on cooling by optimizing setback windows and using presence sensing (FSEC/UCF field data). Where they help most is by preventing the classic homeowner mistake of setting back to 85°F while gone all day.

For a humid Florida climate specifically, look for a smart thermostat with an active humidity setpoint and an overcool-to-dehumidify mode. Ecobee’s implementation is the strongest example: you can tell it “keep humidity below 55%” and it will keep cooling 1°F to 2°F past temperature setpoint if humidity is still high. Nest’s baseline humidity handling is weaker.

Important limitation: a smart thermostat cannot dehumidify without cooling. If the humidity problem is bigger than “run the AC a little longer” (a poorly-sized system, a leaky duct system, or a house tighter than the AC can handle), no thermostat will fix it. You need a dedicated whole-home dehumidifier tied into the ductwork.

Vacation Settings (More Than a Week Away)

When you’re leaving a Florida home unoccupied for more than a week in summer, comfort stops being the goal. Preventing mold is the goal. The right setting looks like this:

  • Thermostat: 78°F to 80°F (do not go higher — you’re now trading a few dollars of savings for real mold risk)
  • Humidity target: below 60% — set your smart thermostat’s vacation mode with humidity control active
  • If you have a whole-home dehumidifier: set it to hold 55%
  • Have someone check the house weekly — a tripped breaker or a clogged AC condensate drain during a two-week Florida absence can leave you coming home to real damage. Or, invest in an iFLO.

Four Florida Thermostat Myths That Cost You Money

1. “Turning the AC completely off saves the most money.”

False in Florida. While the AC is off, humidity keeps rising. When you turn it back on, it has to remove both temperature and hours of accumulated moisture. On a hot-humid day, that recovery cycle can run for two-plus hours and use as much or more energy than a modest setback would have used all day.

2. “Cranking the thermostat down to 68°F cools the house faster.”

False. Your AC produces cool air at the same rate whether the thermostat is set to 76°F or 68°F. Setting it lower just means it runs longer, uses more energy, and (if you forget to raise it) overcools the house.

3. “A ceiling fan lowers the room’s temperature.”

False. Fans cool skin, not air. If nobody is in the room, the fan is spending electricity to heat the room slightly with motor waste heat. Turn fans off when you leave, and only turn them on when they let you raise the thermostat.

4. “78°F is uncomfortable in Florida, so DOE’s advice doesn’t apply here.”

Half true. Most Florida homeowners we work with prefer 72°F to 74°F for daytime comfort, and that’s a legitimate comfort choice, not a mistake — you’re trading some energy savings for how the house feels. But the underlying DOE advice (small daily setback, don’t turn it off during the day, cap the setback around 4°F) applies at any base temperature. If your house feels bad no matter where you set the thermostat, the lever is humidity, not temperature: at 45% RH, 78°F feels comfortable; at 65% RH, even 74°F feels sticky.

When to Call a Pro Instead of Just Adjusting the Thermostat

If you’re already at 76°F and your house is still uncomfortable, or if your electric bill this summer is meaningfully higher than last summer at the same setpoints, the thermostat isn’t the problem. Common culprits we find in Broward and Palm Beach County homes:

  • Oversized system. Too big an AC cools the space fast, shuts off before dehumidifying, and leaves you sticky. Sizing is fixed by a load calculation and equipment swap.
  • Undersized or aging system. The AC runs constantly and still can’t catch up on a hot afternoon. Time for a service call and a capacity check.
  • Leaky ductwork in the attic. A common Florida problem. You’re paying to cool your attic. Fixed with duct sealing.
  • Other sneaky leaks. Check out our full list here.
  • Clogged evaporator coil or condenser coil. Reduces both cooling capacity and moisture removal. Fixed with a tune-up.
  • A dying capacitor or slow-starting compressor. The AC runs but doesn’t remove heat efficiently. Fixed with a diagnostic and part replacement.

If any of that sounds familiar, we’re happy to take a look. Request a service quote or call our team at (954) 454-6801.

Frequently Asked Questions

What is the ideal summer thermostat setting for a Florida home?

For most Southeast Florida homes: 72°F to 74°F when you’re home and awake (this is what most SE Florida homeowners actually run — the DOE savings-max recommendation is 76°F to 78°F if you’re prioritizing bill over comfort), 70°F to 73°F while sleeping (closer to the sleep-research ideal), and 76°F to 78°F while away for the day (never higher than 82°F). Indoor humidity should stay below 60%, ideally 45% to 55%.

Is it bad to turn the AC off during the day and cool the house at night?

In a humid Florida climate, yes. Aggressive setback (letting the house drift up to 85°F or higher during the day) allows indoor humidity to climb past the 60% mold-risk threshold set by EPA, and forces the AC into a long, hard recovery cycle when you get home. A small setback of 2°F to 4°F is fine and can save energy. Anything larger tends to backfire.

How much does each degree of thermostat setback save?

DOE’s published cooling range is 6% to 18% saved when moving from 72°F to 78°F (a 6-degree change). EPA has publicly cautioned that there is no research-supported per-degree savings figure that generalizes across climates and equipment. Florida field data from the Florida Solar Energy Center measured an average 9.5% savings from smart-thermostat programs, on the modest end of the national range.

Does a ceiling fan actually lower my cooling bill?

Only if you raise the thermostat when you turn it on. DOE says a ceiling fan lets you set the thermostat about 4°F higher with equivalent comfort. FSEC found that Florida homeowners in their field study didn’t actually raise the thermostat, so metered savings were zero. The fan alone does nothing; the thermostat change does. And turn the fan off when you leave the room — fans cool people, not rooms.

What thermostat setting should I use when I go on vacation?

Set the thermostat to 78°F to 80°F with humidity control active. The goal shifts from comfort to mold prevention. Do not turn the AC completely off, and do not set the thermostat higher than 82°F for a Florida summer absence longer than a few days. If you have a whole-home dehumidifier, set it to hold 55% relative humidity.

Will a smart thermostat solve my humidity problem?

Only if the humidity problem is small. A smart thermostat with active humidity control (Ecobee is a good example) can overcool 1°F to 2°F past setpoint to dehumidify, which helps. But a smart thermostat cannot dehumidify without running the AC. If your house has bigger humidity issues (oversized equipment, leaky ducts, tight construction), you need a whole-home dehumidifier tied into the ductwork, not a thermostat upgrade.

Sources

Request Service