When you get home, the most energy efficient thermostat setting for summer is around 72-76°. Don't drop the temperature lower than that, expecting the house to cool off faster.
The U.S. Department of Energy recommends 78° as the best temperature setting for your air conditioner during the daytime. And 82° for sleeping in the summer.
Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.
When temperatures exceed 100 degrees Fahrenheit outside, setting your air conditioning (AC) to around 75-78 degrees Fahrenheit is generally considered efficient. Here are some reasons for this recommendation:
During a heatwave, we recommend that you don't lower the AC's setting below 68°F. This is already quite chilly for most people, and many would consider it too cold. An air conditioner set this low risk of its coil freezing—and that's bad news because it indicates that the air conditioner is overworked.
70°F is an ideal temperature setting, regardless of how hot it gets outside. This is a comfortable temperature for most, though you may find that it can feel too cold at times. Any air conditioner set lower than this is at risk of having its coil freeze.
Clean the Thermostat
Sometimes, when the room temperature doesn't match the thermostat setting, the problem could be dirt buildup on its interior parts. A dirt coating around the inner components may create excess heat and cause the thermostat to give the wrong readings.
For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.
For the most efficient performance, set the thermostat 20 degrees lower than the temperature outside. On a 100℉ day, set it to 78℉ to 80℉ to manage utility costs. If there's a lack of airflow, the filter may need to be changed or AC vents cleaned.
The average summer temperature is around 71°F. In winter, this falls just a touch to 70°F. Here's a winter breakdown for thermostat settings across the U.S., according to the survey participants: 47% set it between 68°F and 71°F.
Summer Air Conditioner Settings
In the summer, experts say the thermostat for your air conditioner should be set to at least 78°F during the day when people are at home.
Setting the thermostat below 72 degrees while using an air conditioner can cause the unit to work harder than necessary, leading to higher energy bills and potential damage to the appliance.
In most cases, air conditioners only have one speed (though some have variable speed settings to improve energy efficiency). Lowering the temperature too much causes your air conditioner to operate longer, causing more wear and tear on it as well as higher utility bills.
Our recommendation: When you head to work or vacation and want to lower your temperature setting, we would not recommend going below 50 degrees F. This strikes a good balance between conserving energy while preventing problems such as: Frozen indoor pipes. Damage from condensation on furnishings and electronics.
You want to be comfortable, but also use an efficient temperature that doesn't potentially increase your energy costs. The best thermostat setting for summer is 78 degrees Fahrenheit when you're at home. Energy.gov also suggests raising your thermostat or turning it off entirely when you are away in the summer.
The best AC temperature for sleeping
The goldilocks zone: Aim for a temperature between 18°C (64°F) and 22°C (72°F) for optimal sleep comfort. Individual needs: Consider personal preferences and adjust the temperature accordingly. Some people may prefer slightly cooler or warmer settings.
For example, HVAC specialists recommend setting your thermostat no lower than 20 degrees the outside temperature. Suppose the outdoor temperature in your area is a blistering 90 degrees Fahrenheit. It's probably best to keep your thermostat between 70 and 80 degrees Fahrenheit to prevent stress on your unit.
For instance, if it's 100 degrees outside, aim to set your thermostat to at least 80 degrees. Adhering to the 20-degree rule maintains energy efficiency, prevents strain on your cooling system, extends its lifespan, and promotes lower energy bills and consistent indoor comfort.
Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.
What should my AC be set at if it's 90 degrees outside? If the outdoor temperature is 90 degrees, it's recommended to set your thermostat between 75-78 degrees.
Negative Health Effects
Another reason not to set your AC too low is for the sake of your health. A thermostat set to 68 degrees F or lower, can create temperature imbalances within the room. This could result in making certain areas uncomfortably cold while others remain warmer.
Is 65 degrees cold for a house? During the summer, 65 degrees might use a lot of energy and be too cool for a house, but this temperature can save energy during the winter. It all depends on your personal preferences.
To combat these hot and often humid conditions, it may be necessary to drop your temperature setting below 78 degrees to 72-74 degrees Fahrenheit. However, if everyone in your home is still at school or working, you may want to leave the temperature set at 78 to avoid cooling an empty house.
U.S. Department of Energy research suggests that setting your programmable thermostat to 78 during the summer months is the best way to save money on your cooling costs while maintaining a comfortable temperature.
Check for dust, dirt, and other kinds of residue inside the thermostat. Excessive dust and dirt buildup can prevent your thermostat from working properly. Clean any residue you see on the thermostat, and see if that helps improve the temperature in your home.