If the outdoor temperature is 90 degrees, it's recommended to set your thermostat between 75-78 degrees.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
Simply put, it means you should never set your thermostat for a temperature more than 20 degrees cooler than the outside air. Why not? Most air conditioning systems can only handle a 20-degree difference between the outside and inside air temperatures.
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.
Setting your air conditioning to 72°F is generally considered a comfortable indoor temperature for many people. It strikes a good balance between comfort and energy efficiency, making it a popular choice for residential settings.
Most people work better and are more productive when with a temperature setting in the 72–74-degree range. This setting is low enough to keep the house cool and dry and keep you and the kids awake during the afternoon hours.
Best AC Temperature Settings While You Are Home
As you consider the most comfortable room temperature for your lifestyle and family, keep in mind that for each degree that you set your thermostat above 72 degrees, you can save up to 3% on your energy bill.
On average, an air conditioner running in good condition should take about 15-20 minutes to drop the temperature by 1 degree in a standard-sized room. However, factors like outside temperature, unit size, and insulation quality can affect this timing.
Recommended Temperature When You Are Home
The World Health Organization (WHO) recommends setting your thermostat no lower than 64 degrees (F) in the Winter months while people are in the home. If there are infants or elderly individuals, they recommend keeping the temperature at 70 degrees at a minimum.
Cooling a house from 90 degrees to 72 degrees typically takes about 2 to 4 hours, depending on various factors.
The 20-degree rule is a guideline suggesting that the indoor temperature of your home should not be set more than 20 degrees below the outdoor temperature. This rule is recommended to prevent your AC unit from overworking, which can lead to high energy bills and potential maintenance issues.
A dirty air filter
Your air filter is designed to trap contaminants in the air before it gets pulled into the AC system. But over time that means that your filter gets dirty and clogged. And if a dirty filter isn't replaced, it can seriously limit your AC's cooling power.
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.
Air conditioners shouldn't generally work all the time unless the thermostat is set to “fan on” (inadvisable). A correctly sized and well-maintained AC system should run for 15 to 20 minutes, two or three times every hour—with longer cycles in the higher temperatures of summer.
Just because the outdoor temperature is above 100, the Ideal temperature to set your AC unit to doesn't change — it's 78 degrees.
Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.
Nighttime: “Lower the thermostat setting by a few degrees during the night, ideally around 62°F-65°F,” suggests Roberson. To ensure you're nice and toasty, call on extra blankets and warm PJs before you kick up the thermostat.
Dirty air filters are generally the culprit for most air conditioner problems. If your air conditioner is running all day long but not lowering the temperature at home, check your air filters. If they are dirty, simply swap them out for new ones.
The hotter it is outside, the longer your air conditioner must run to reach the desired temperature. Don't be alarmed if cycles last longer than 20 minutes on a 95-degree day, especially if it's also humid outside.
Here's the thing: It's normal for your AC to run continuously during hot summer months. You see, on extremely hot days—we're talkin' high 90s to 100s—your system needs to keep up with the incoming heat. To do that, it will run longer in order to maintain a constant, desired temperature in your home.
What is the Best Thermostat Setting for Summer Air Conditioner Use? Energy Star recommends the following thermostat temperatures for your air conditioner in the summer: 78°F during the day if people are home. 82°F at night if people are home.
The best way to save money is by combining both. The “run” feature lets you preset the temperature when you're not home to prevent wasting money on cooling or heating an empty home. Meanwhile, the “hold” button lets you change the room's temperature without changing your energy-saving, preset schedule.
Finding the right AC temperature for your electricity bill is a balancing act. By setting it around 78°F and considering external factors, you can enjoy comfort and save on energy costs simultaneously. Remember, small adjustments can lead to significant savings over time.