How Cool Should My Home Be If It's Over 100 Degrees Outside? Just because the outdoor temperature is above 100, the Ideal temperature to set your AC unit to doesn't change — it's 78 degrees.
Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits. If you set your thermostat to much lower than the upper 70s, you could hinder the operation of your air conditioner and increase your energy costs.
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 air conditioners will max out at cooling your air to about 15-20 degrees cooler than the air outside. If the temp outside is 100 degrees, your unit will struggle to keep the temperature in your home consistent at 80 degrees. The hotter it gets outside, the less temperature difference your AC unit will provide.
During heat waves, experts, including utility companies, recommend keeping your thermostat no more than 20 degrees cooler than the outdoor temperature. For instance, if it's 100 degrees outside, aim to set your thermostat to at least 80 degrees.
Recommended thermostat setting
The utility recommends a setting of 78 degrees when you're home, even though it's a saunce outside, and 82 degrees when you're not home. “Summer heat is tough on air conditioning units,” FPL says,”but cooling your home doesn't have to break the bank. Keep your energy costs under control.”
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.
If your air conditioner isn't keeping up with the heat, your air filter may be to blame. A dirty air filter can obstruct the airflow path through the unit. Using a dirty air filter can also cause less energy efficiency and more costly utility bills.
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.
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.
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.
Cool mode: Ideal for hot days, this mode reduces the room temperature to your desired setting. Dry mode: Perfect for humid conditions, this mode removes excess moisture from the air without significantly reducing the temperature.
The highest environmental temperature humans can survive is 104°F to 122°F (40°C to 50°C). But those temperatures aren't safe. A safe temperature range for prolonged outdoor time is 77°F to 88°F (25°C to 31°C).
What is a Good Temperature to Set Your Thermostat in the Summer? Every season has an ideal thermostat temperature and for summer the U.S. Department of Energy suggests that when home, 78 degrees is the sweet spot between staying cool and keeping your energy bill low.
When outside temperatures are pushing 100 degrees, try setting your thermostat at 78-80 degrees. Supplement the indoor airflow with fans and other strategies to maintain cool temperatures inside.
Rochester Electric and Gas recommends setting your thermostat at 78 degrees or higher, as each degree above 75 degrees saves 3% of energy on cooling. A higher internal temperature actually slows heat flowing into your living space, so it saves additional money on air conditioning.
If the outdoor temperature is 90 degrees, it's recommended to set your thermostat between 75-78 degrees. This setting strikes a balance between comfort and energy efficiency. Lowering the thermostat setting too much can cause the AC to run continuously, leading to higher electricity bills and more frequent repairs.
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.
Larger AC units may cool your home faster, but that means the cooling cycle will end faster and they will shut down faster – only to cycle back on again before very long. This rapid cycling creates a lot of wear and tear on the system, shortening its life and increasing the maintenance needed to keep it running.
How Cool Should My Home Be If It's Over 100 Degrees Outside? 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.
The agency's official position is that you can save “up to 10 percent on heating and cooling settings by simply turning your thermostat 7°-10°F for 8 hours a day from its normal setting.” In other words, if you keep it at 71 while you're home, go ahead and set it to 78 if you leave for the day.