In short, the 20-degree rule of air conditioning states that you should always keep your AC unit at no more than 20 degrees lower than the outside temperature. It means that, if the outdoor conditions are at 95 degrees, you should set your thermostat at no less than 75 degrees.
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:
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.
68 to 72 degrees is a temperature range that is not too warm or cool, and is sufficient enough to warm up the home just enough so that everyone is comfortable regardless of the type of clothing they have on.
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.
In short, the 20-degree rule of air conditioning states that you should always keep your AC unit at no more than 20 degrees lower than the outside temperature. It means that, if the outdoor conditions are at 95 degrees, you should set your thermostat at no less than 75 degrees.
Still, if you can make your indoor temperature about 25 degrees warmer than outside, then you will save money and remain heated. If the temperature is 30 degrees (or lower) outside, turn your thermostat up to at least 60 degrees, you will notice the difference.
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.
Keeping your home warm in the winter is essential for one's comfort and also to keep pipes from freezing. However, you should be mindful of energy consumption as well. According to the Department of Energy, the optimal temperature setting for homes during freezing weather is 68 °F.
While ENERGY STAR suggests 82 degrees, that may be too uncomfortable for most families. Most people sleep better when their sleeping area is chilly, so that's why the National Sleep Foundation advises 60–67 degrees.
According to the Department of Energy, the best temperature to set an AC unit is 78°F when home during the day. However, we know that adjusting the thermostat can feel like a game of hot and cold, especially when trying to find that sweet spot during summer heat waves.
If you have the thermostat set at 20, for example, the heating will come on when the temperature in that room falls below 20, and once it gets back up to 20 it'll turn off again.
Daikin Multi Split Systems can heat or cool multiple rooms using only one outdoor unit connected to multiple indoor units. Each indoor unit can also be individually controlled, scheduled and set to the desired room temperature.
Just because the outdoor temperature is above 100, the Ideal temperature to set your AC unit to doesn't change — it's 78 degrees. Higher temperatures in the home are to be expected when the weather is hotter than usual, but your thermostat can still be set the same as if it were a lower temperature outside.
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.
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 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.
There may be drafts and pockets of colder air near the floor; The walls are colder and don't emit the usual amount of infrared radiation, so you lose heat due to your body emitting more IR than it receives; You may spend more time indoors and hence have less physical activity, so your body generates less heat.
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.
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.
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.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
It's advisable to keep your home below 80 degrees throughout the summer. A house that's too warm can be dangerous to people, pets, and the soft surfaces in your home. Set the winter temperature to 68 degrees when you're awake and 62 degrees when you're sleeping.
The best room temperature for sleep is approximately 65 degrees Fahrenheit (18.3 degrees Celsius). This may vary by a few degrees from person to person, but most doctors recommend keeping the thermostat set between 65 to 68 degrees Fahrenheit (15.6 to 20 degrees Celsius) for the most comfortable sleep.