If your summer electric bills seem to climb faster than the temperature outside, it may be time to take a closer look at your thermostat.
Every year, homeowners across Springfield, Hendersonville, White House, Gallatin, Portland, and surrounding Middle Tennessee communities start asking the same question:
What’s the best thermostat setting for summer?
It’s easy to assume that turning the thermostat way down will cool your home faster or that raising it dramatically while you’re away will save the most money. In reality, both approaches can create unnecessary strain on your air conditioner and lead to higher energy costs.
A few smart adjustments can help lower cooling costs, improve comfort, and reduce wear on your HVAC system throughout the summer, helping reduce the likelihood of unexpected AC repairs during the hottest months of the year.
At Petitt Heating & Cooling, we help homeowners make these decisions every day. Here’s what we typically recommend for staying comfortable without overspending during a Middle Tennessee summer.
Quick Answer: What Is the Best Thermostat Setting for Summer?
For most homeowners, 78°F is the best thermostat setting for summer when you’re home. Raise the temperature to 82–85°F when you’re away and lower it slightly while sleeping based on personal comfort.
These settings help reduce energy use while keeping your home comfortable during hot weather.
Why Lowering the Thermostat Doesn't Cool Your House Faster
One of the most common misconceptions homeowners have is that setting the thermostat dramatically lower will cool the house more quickly.
It won’t.
Your air conditioner cools at the same rate whether you set the thermostat to 75°F or 65°F. The only difference is how long the system continues running before it shuts off.
That means dropping the temperature far below your target setting often leads to:
- Higher energy bills
- Longer run times
- More wear on your HVAC system
- Unnecessary strain during extreme heat
If your goal is to reach 74°F, simply set it to 74°F and let the system do its job.
The Best Thermostat Setting When You're Home
For most households, an internal temperature of 78°F offers the best balance between comfort and efficiency.
The U.S. Department of Energy recommends this setting because it allows your air conditioner to operate efficiently while still keeping indoor temperatures comfortable for most people.
That said, comfort matters.
If 78°F feels a little warm for your family, moving the thermostat down a degree or two isn’t going to ruin your budget.
Most homeowners are surprised by how little they notice a one- or two-degree change, especially when it can help reduce cooling costs throughout the summer.
The Best Thermostat Setting While You Sleep
Most people sleep better in a slightly cooler environment.
For many homeowners, the ideal nighttime temperature falls somewhere between 74°F and 78°F
The exact number depends on:
- Personal preference
- Bedding
- Humidity levels
- Air circulation
This is one area where experimenting can help. A small adjustment can often improve sleep quality without creating a noticeable increase in energy usage.
The Best Thermostat Setting When You're Away
If nobody is home during the day, there’s no reason to keep the house at the same temperature.
A common recommendation is 82°F to 85°F while you’re away.
This allows your air conditioner to run less frequently while still preventing the home from becoming excessively hot.
Many homeowners make the mistake of turning the thermostat way up before leaving and then cranking it way down when they return.
That’s usually not necessary.
Moderate adjustments tend to provide the best balance between comfort and efficiency.
What Should You Set Your Thermostat To During Vacation?
Vacation settings are a little different.
If you’ll be gone for several days or longer, most homeowners can safely set the thermostat between 85°F and 88°F
This helps reduce cooling costs while still protecting:
- Indoor humidity levels
- Furniture
- Electronics
- Flooring
- Household belongings
You don’t want the house to become excessively hot and humid, especially during a Middle Tennessee summer.
The goal is to reduce unnecessary cooling, not completely shut the system down.
Why Big Temperature Swings Can Work Against You
Many homeowners try to save money by making large thermostat adjustments throughout the day.
For example:
- 68°F at night
- 85°F during the day
- 72°F after work
While it sounds efficient, these large swings can actually create comfort problems and force the system to work harder when trying to recover.
Smaller adjustments tend to be more effective.
Instead of constantly chasing different temperatures, focus on maintaining reasonable settings that keep your home comfortable without creating major recovery periods.
The Easiest Way to Save Money: Let a Smart Thermostat Do the Work
This is where smart thermostats really shine.
Instead of manually adjusting temperatures throughout the day, a smart thermostat can automatically follow a schedule based on your routine.
Benefits often include:
- Automatic temperature adjustments
- Energy-saving schedules
- Remote control from your phone
- Usage tracking
- Improved comfort consistency
Many homeowners are surprised by how much easier it becomes to manage cooling costs once the thermostat is handling the adjustments automatically.
Perhaps more importantly, it eliminates the guesswork.
No more forgetting to raise the temperature before leaving for work. No more returning from vacation to a house that feels like a sauna.
The system handles it for you.
Other Ways to Reduce Summer Cooling Costs
Thermostat settings matter, but they’re only part of the equation.
Your air conditioner also needs proper airflow and efficient operation to keep cooling costs under control.
A few simple habits can help:
Change Your Air Filter Regularly
A clogged filter restricts airflow and forces your system to work harder than necessary.
Keep the Outdoor Unit Clear
Grass clippings, leaves, and debris can reduce efficiency and restrict airflow around the condenser.
Close Blinds During Peak Afternoon Heat
Reducing solar heat gain helps your AC maintain indoor temperatures more efficiently.
Schedule Routine Maintenance
Small issues often become expensive repairs when they’re ignored.
A professional AC tune-up can help identify efficiency problems before they affect comfort or increase utility costs.
When Thermostat Adjustments Aren't Solving the Problem
If your thermostat settings seem reasonable but your energy bills continue climbing, the issue may not be the thermostat at all.
Common problems include:
- Dirty coils
- Low refrigerant
- Duct leaks
- Poor insulation
- Aging HVAC equipment
- Airflow restrictions
If your system struggles to maintain temperature, runs constantly, or creates unusually high energy bills, it’s worth having the equipment evaluated.
Sometimes the most effective way to lower cooling costs is solving an underlying HVAC issue.
Frequently Asked Questions About Summer Thermostat Settings
Why does my house feel humid even when the AC is running?
High indoor humidity can be caused by an oversized air conditioner, restricted airflow, dirty coils, ductwork issues, or an AC system that isn’t removing moisture properly. If your home feels sticky despite running the AC, it may be worth having the system evaluated.
How often should a thermostat be replaced?
Most thermostats last around 10 years, but older models can become less accurate over time. If your thermostat struggles to maintain temperatures, frequently needs adjustments, or lacks energy-saving features, it may be time for an upgrade.
Can closing vents in unused rooms save money?
Usually not. Most HVAC systems are designed to distribute air throughout the entire home. Closing multiple vents can disrupt airflow, reduce efficiency, and sometimes increase strain on the system.
Why does my thermostat say one temperature while the house feels different?
Thermostat placement can affect temperature readings. Direct sunlight, nearby vents, kitchens, and other heat sources can cause inaccurate readings that don’t reflect the actual comfort level throughout the home.
How much can a smart thermostat save on energy bills?
Savings vary by household, but many homeowners see noticeable reductions in cooling costs because smart thermostats automatically adjust temperatures based on schedules, occupancy, and usage patterns.
Stay Comfortable This Summer Without Overworking Your AC
Finding the right thermostat setting isn’t about making your house as cold as possible. It’s about finding the balance between comfort, efficiency, and long-term system performance.
If your cooling bills seem unusually high, your home never feels comfortable, or you’re interested in upgrading to a smart thermostat, the team at Petitt Heating & Cooling is here to help.
We’ll help you identify what’s driving your energy costs and recommend practical solutions that make sense for your home, your comfort goals, and your budget.
Call today or schedule service online to keep your home comfortable all summer long.