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Does Setting Your Thermostat to 78°F Really Save Money? Here's the Truth

Updated: Jun 12

Young adult adjusting the temperature on smart thermostat in kitchen

Curious if setting your thermostat to 78°F really cuts your cooling costs?

The short answer is yes.

The Key:

Maintain an indoor temperature close to the outdoor temperature while you're home and increasing it when you're away.

This approach helps your HVAC system operate more efficiently by reducing energy consumption thus lowering your utility bills.

Here's everything you need to know on how thermostat settings can lower cooling cost.

Let's dive in:

Setting Your Thermostat Efficiently

Setting your thermostat to 78°F when it's 82°F outside might seem counterintuitive,

but it's actually an effective way to balance comfort and energy savings. Here’s why this strategy works:

The Principle Behind 78°F

  • Minimized Temperature Difference:  The smaller the difference between the indoor and outdoor temperatures, slows the flow of heat into your home, reducing energy consumption and thus lowers your utility bills.

  • Comfort Balance:  78°F is generally considered a comfortable indoor temperature for most people, especially if you're wearing light clothing and using fans to circulate air.

  • Humidity Control:  Air conditioning units also dehumidify the air. By setting your thermostat to 78°F, you can maintain a comfortable humidity level, which can make the indoor temperature feel cooler than it actually is.

Enhancing Comfort

To enhance comfort while keeping your thermostat set at 78°F, consider these tips

  • Use Ceiling Fans:  Fans can make a room feel cooler by circulating air, allowing you to feel comfortable at higher temperatures.

  • Close Blinds and Curtains:  Block out direct sunlight during the hottest parts of the day to reduce indoor temperatures.

According to U.S. Department of Energy, raising AC temps can cut cost by about 3% for each degree increased. Upgrade to Energy Star certified AC Systems for up to 15% more efficiency.

The Energy Savings

By setting your thermostat to 78°F when you're home and increasing it when you're away, you can save on energy costs without sacrificing comfort. According to the Department of Energy, you can save about 3% on your cooling costs for each degree you raise the thermostat. This adds up to significant savings over the course of the summer.

Practical Example

Let’s say your air conditioning costs are $700 during the summer in Massachusetts.

Between June and September, the average cost of home cooling will be $719, up nearly 8% over last year, according to projections from the National Energy Assistance Directors Association (NEADA) and the Center for Energy, Poverty, and Climate (CEPC).

Setting your thermostat to 78°F and increasing and adjusting the temperature while away can save you approximately 10% on cooling cost, about $72 for the summer, as you reduce the energy needed to maintain a cooler indoor temperature. Upgrading your HVAC system to an Energy Star® rated system can save you up to 20% on cooling costs, that's $140 savings for the summer.


Programmable Thermostats: Set it & Forget it

Using a programmable thermostat allows you to set a schedule for your heating and cooling, adjusting the temperature automatically based on your daily routine.

By programming it to follow multiple daily settings—typically 4 or more temperature changes a day—you can optimize energy use without constant manual adjustments. Here's a closer look at how you can use these settings effectively.

Thermostat Summer Temperature Schedule

To maximize savings and comfort, consider the following schedule for adjusting your thermostat:

  • Morning (6:00 AM - 9:00 AM): Set your thermostat to your preferred comfort level as you wake up and get ready for the day. This might be around 72°F to 74°F.

  • Daytime (9:00 AM - 5:00 PM): Increase the temperature by 7-10 degrees if the house is empty. Set the thermostat to around 78°F to 82°F if you're at work or away.

  • Evening (5:00 PM - 10:00 PM): Lower the temperature back to a comfortable level when you return home. This might be 72°F to 74°F.

  • Night (10:00 PM - 6:00 AM): Set the thermostat slightly higher while you sleep, around 75°F to 78°F. Some people prefer a cooler sleeping environment, so adjust based on your comfort.

Conclusion: Setting Your Thermostat to 78°F

By setting your thermostat efficiently and making thoughtful adjustments, you can enjoy a comfortable home while also reducing your energy bills throughout the year.

In the summer, maintaining a temperature close to the outdoor level (around 78°F) allows your HVAC system to operate more efficiently by reducing energy consumption. This not only keeps you cool but also minimizes unnecessary energy costs.

For added comfort and to maximize energy savings, consider the following adjustments:

  • During the day: Increase the thermostat setting by 7-10 degrees when the house is empty.

  • During the evening: Lower the thermostat back to a comfortable level when you return home.

  • At night: Set the thermostat slightly higher to save energy while you sleep.

In winter, the same principles apply: set your thermostat to around 68°F to 70°F while you're awake, and lower it when you're asleep or away. This helps slow down heat loss from your home, saving energy and money.

One common misunderstanding is the idea that setting the thermostat to a lower temperature results in faster cooling.

However, this can actually lead to increased energy consumption. Instead, setting the thermostat at a moderate, comfortable level allows your air conditioning system to operate more efficiently, conserving energy and reducing overall utility costs.

By following these guidelines, you can make small adjustments to optimize both comfort and savings in your home, ensuring a comfortable environment and reducing energy bills throughout the year.

Ready to take control of your home’s comfort?