Temperatures Above 100 Degrees Fahrenheit When temps reach above 100, expect lower AC performance and potential breakdowns.
When it comes to maintaining a comfortable indoor climate while saving on energy costs, it's crucial to understand the minimum temperature for running your air conditioner. The lowest outside temperature at which to run your AC is typically around 60-65 degrees Fahrenheit.
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:
Anything below 65 F is dangerous. Compressor compress gas and if the refrigerant condense before going into the compressor and liquid is incompressible, then the motor will stall and the connecting rods and bearings could be damaged.
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.
Temperatures Above 100 Degrees Fahrenheit
Most air conditioning systems are designed to function with outside temperatures of 100 degrees or less.
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. But it might not be able to cool it down to 70 degrees during the heat of the day.
It's summertime, and you've noticed your AC never stops running. Should you be concerned? 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.
While most AC units can still function in higher heat, they begin to struggle, with a maximum operational temperature usually around 120 degrees. Beyond this, the unit's ability to cool effectively diminishes, and it may even stop working altogether.
Most central air conditioners can cool a moderate-sized (3 to 4 bedroom) home by about 5 degrees every 3 hours. This means while it can take no more than a couple hours to lower the temperature to a comfortable range in the fall or autumn, it can take much longer in the 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. 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.
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.
How one perceives and responds to heat varies from person to person, but the Occupational Health and Safety Administration says that a wet bulb temperature (a more accurate method of understanding heat risk by measuring temperature, humidity, and sunlight) of 77 degrees or more can make strenuous work unsafe.
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.
A broken air conditioner may be considered an emergency in any of the following situations: Your AC has broken down on an extremely hot day (above 90 degrees) You have young children, elderly adults, or immune-compromised people in your home that may be sensitive to excessive heat.
But an ac unit can run in ac mode even in the winter time. Refrigerant acts differently below 61 degrees and running a compressor below this temperature can damage it.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
The compressor is located in your AC's outdoor unit and when this unit is covered in grime/dirt/leaves, the compressor can't work properly, which forces the AC to run longer and harder. Eventually, the compressor overworks itself and the AC overheats.
In most cases, especially in residential applications, you should not run your air conditioner when outdoor temperatures are below 60 degrees. The air conditioner does function, but you are going to burn out the compressor fairly quickly.
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.
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.
Increased Energy ConsumptionEvery time you adjust your thermostat, your HVAC system has to work harder to reach the desired temperature. This constant fluctuation in temperature settings often leads to increased energy usage, translating into higher utility bills.
In extreme heat, you might notice your air conditioner isn't as effective, and your energy bills could be higher. Here's why: High temperatures put extra stress on the AC, which can lead to parts like fan motors and compressors getting too hot. This can cause uneven cooling or even damage the system.
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.
Fans do not cool the air, so air currents flowing over the body must be cooler than your body temperature to cool you down. When indoor air temperatures are hotter than about 95 °F: Fan use may cause your body to gain heat instead of lose it.