But what does that mean? 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.
Your air conditioner will be able to cool to about 15-25 degrees from the outside temperature. If it's 95 degrees outside, and you set your thermostat at 65 degrees, there's almost no chance your system will get the indoors to 65 degrees.
A temperature of 72°F (22°C) is generally considered a comfortable setting for air conditioning. It strikes a balance between comfort and energy efficiency. Here are some points to consider:
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:
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.
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.
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.
It's true that air conditioners do have limits when the outside temperature is extreme. This means that your air conditioner may be able to keep your home at 77 or 78 degrees when it is 104 degrees outside.
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.
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.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
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.
For most people, 75 degrees is too hot to sleep, per the National Sleep Foundation. But the new study found that in people 65 and up, sleep efficiency only started to decrease when temperatures were above 77 degrees.
Typically, it takes about an hour for an average-sized air conditioning unit in typical conditions to lower room temperature by one degree Fahrenheit. But remember, 'average' doesn't mean 'always'. Like people, every AC has its personality – some are sprinters while others prefer marathons.
Running the AC unit full-time in our big house example would cost $7.39 per day for the efficient unit, or about $222 per month. For the less efficient unit, you're looking at $10.56 per day or about $317 per month. Not only that, but running all day is hard on your air conditioner.
Many say that if you set your thermostat to a single, specific temperature, your HVAC system will use less energy. The logic behind this is that you won't be turning it on and off or making the system cool and reheat the home. This usually is not the case unless your HVAC system has a heat pump.
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.
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.
Your AC might be stuck at 75 due to various reasons like clogged filters, refrigerant leaks, or the wrong unit size. It's best to have a professional diagnose and fix the issue.
The constant running of your AC unit will reduce pressure in the evaporator, or cooling coil until it freezes over, according to Cool Today. This is why in some cases, this constant running can be dangerous.
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.
Proper airflow is crucial for an AC system to cool your home efficiently. Several factors can compromise airflow, including blocked or obstructed vents, closed or incorrectly adjusted dampers, and dirty or obstructed evaporator coils. These issues restrict the air's flow, reducing the system's cooling capacity.
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.
In summer, the best mode for your air conditioner is the "Cool" mode, set to a comfortable temperature around 78°F when you're home. This setting efficiently reduces indoor humidity and maintains a comfortable environment without overworking the AC system.
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.