Once and For All: Should You Adjust Your Thermostat Throughout the Day?

By Michael Franco

June 01, 2025

When the heat of summer kicks into high gear, many homeowners start playing the thermostat game. Should you leave it at a constant temperature all day, or adjust it depending on whether you’re home or not? You might think that the answer depends on what you value most — comfort, cost savings or system longevity — but the good news is, you don’t have to sacrifice one for the other. When used thoughtfully, your thermostat can help you stay cool while also saving money and energy.

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So, once and for all: Is it really worth adjusting your thermostat throughout the day in the summertime? Let’s break it down.

The Case for Adjusting Your Thermostat

The short answer is yes — adjusting your thermostat based on your daily routine can significantly reduce your energy use and lower your utility bills. The U.S. Department of Energy estimates that you can save up to 10% a year on heating and cooling by turning your thermostat back 7° to 10°F for 8 hours a day. That kind of savings adds up over a long, hot season.

When no one’s home during the day, there's no reason to keep the house as cool as when you're sleeping or lounging around in the evening. Raising the thermostat even a few degrees during those off-hours means your AC runs less often, which translates to reduced energy consumption and a lighter load on your cooling system.

Understanding Thermostat Energy Efficiency

Your air conditioner doesn’t work harder to cool the house back down after a higher daytime setting — that’s a myth. It simply runs until the set temperature is reached. By letting the indoor temperature rise while you’re away, you reduce the number of cycles your system has to run. That not only uses less energy but can also extend the lifespan of your HVAC system by reducing wear and tear.

Let’s say your usual setting is 72°F. If you bump it up to 78°F while you’re at work, your AC will use far less electricity throughout the day. Even better? If you pair that with a smart or programmable thermostat, you don’t have to think about it — the system will handle adjustments automatically based on your preferences and schedule.

Digital, Programmable and Smart Thermostats: Your Summer Sidekicks

Installing a programmable thermostat or a smart thermostat is one of the easiest and most effective ways to get the most out of temperature adjustments. These devices let you schedule changes so your AC isn’t running full throttle when it doesn’t need to.

Many smart thermostats also “learn” your habits over time and can adjust automatically based on when you’re home or away. They even factor in local weather conditions and humidity levels to make intelligent tweaks that balance energy efficiency and comfort.

For example, you can set your thermostat to go up to 78°F when you leave for work, then gradually cool the house down to 74°F just before you arrive home. Overnight, when cooler outdoor temperatures help reduce strain on the system, you can even drop it slightly more if that helps you sleep better.

Ideal Home Thermostat Settings for Summer

While every home and comfort level is different, energy experts generally recommend the following approach for hot-weather efficiency:

  • When you’re home and awake: Set the thermostat to around 74-76°F.

  • When you’re away: Bump it up to 78–80°F.

  • When you’re sleeping: Somewhere between 72–74°F, depending on personal preference and humidity levels.

This schedule keeps you comfortable when you’re home and avoids cooling an empty house unnecessarily. The trick is to avoid large temperature swings — keep the changes reasonable and consistent, not extreme.

What About Humidity?

In hot climates, humidity control is nearly as important as temperature. Some people hesitate to raise their thermostat during the day because they’re worried about excess humidity making the house stuffy or encouraging mold. That’s a valid concern — but modern AC systems and smart thermostats can be set to manage humidity even when the temperature is higher. Some systems include dedicated “dehumidify” modes that keep moisture levels down without overcooling your space.

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Debunking the Constant-Temperature Myth

Some homeowners believe it's more efficient to keep the house at a single temperature all day long because “it takes more energy to cool the house back down.” That’s been repeatedly debunked by experts.

The physics are simple: the greater the temperature difference between the inside and outside of your home, the faster heat moves in. When you keep your home very cool during the hottest parts of the day, your system is fighting harder against that heat transfer. By letting the temperature rise slightly, you reduce that differential — and your system gets a bit of a break.

In other words, the longer your home stays closer to the outdoor temperature (within reason), the less work your AC has to do.

Final Thoughts: Comfort Vs. Savings

Adjusting your thermostat throughout the day can lower energy bills, reduce environmental impact and extend the life of your cooling system — all while still keeping your home comfortable. If you already have a programmable or smart thermostat, you’re ahead of the game. If not, this might be the year to consider an upgrade.

In the end, a consistent yet flexible approach to your thermostat settings is the sweet spot. You don’t need to manually adjust it every hour. A well-planned schedule or smart system can handle it for you — ensuring that you stay cool when you’re home and save money when you’re not.

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