Apart from extreme heat, cold can also affect your air conditioning unit. When temperatures go below 60 F, most manufacturers recommend that you do not try running your AC. It is likely to cause damage because it can cause the parts to freeze.
When temperatures outside become higher than 100 degrees Fahrenheit, the air conditioning system can consume more energy and begin to malfunction or fail. Most air conditioning systems are designed to function with outside temperatures of 100 degrees or less.
But you shouldn't run your AC if the temperature is below 60°F.
Your AC has limits, no matter its age, how well it was installed, its manufacturer, etc. As a rule of thumb, when it's 95 out, your AC can cool your house to approximately 70-80. Your air conditioner will be able to cool to about 15-25 degrees from the outside temperature.
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.
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.
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.
As we mentioned, air conditioners have a maximum temperature limit. When the temperature outside reaches this point, the AC unit will shut down in order to prevent damage. The reason for this is that when an AC unit gets too hot, it puts strain on the compressor.
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.
Can ACs handle 50-degree temperatures? Modern air conditioners are generally rated to operate at a maximum ambient temperature of 55 degrees Celsius. However, in real-world conditions, even at lower outdoor temperatures, the air around the AC unit can be much hotter because it expels heat from the room.
The lowest outside temperature at which to run your AC is typically around 60-65 degrees Fahrenheit.
A common rule of thumb is that most models can function properly only above 68 degrees Fahrenheit. Any lower temperature will result in the system freezing up. In addition to a frosty refrigerant, the piping and coils could also become covered with ice.
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.
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.
Yes, you should turn off your AC if it's not cooling. Continuing to run a malfunctioning AC can strain the compressor and other components, leading to more severe and costly repairs.
Many factors can cause this issue, including clogged filters, refrigerant leaks and the wrong unit size. While it's possible to troubleshoot it yourself, it is best to contact an HVAC professional for your AC problems.
That's why the majority of HVAC companies recommend that you do not turn your AC on if the temperature dips below 60 degrees Fahrenheit. Of course, this doesn't mean that you have to rush home to turn it off if the weather takes an unexpected turn.
Most residential AC units can cool air to around 60-65°F (15-18°C), which is considered comfortable for indoor settings. However, specialized industrial or scientific systems can reach lower temperatures, potentially going as low as -60°F (-51°C).
To fix your air conditioner that is not cooling, you can try resetting your thermostat to the correct setting of AUTO, instead of ON. If you reset your thermostat and your air conditioner is still not working, you should replace your air conditioner's air filter.
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.
Despite running your air conditioning system, you may still find hot spots in certain rooms of your house—particularly in large rooms or in multi-story homes. This problem can be caused by a variety of factors, such as insufficient insulation, a damaged AC system, or ventilation issues.
When the temperature soars, your AC has to work harder to maintain a comfortable indoor climate. It needs to remove more heat from your home, and if it's not properly maintained or appropriately sized for your space, it can struggle to keep up.
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.
Recommended AC Temperature for Sleeping
The Sleep Foundation says 65° is the best temperature for sleeping. However, if you prefer a slightly warmer or cooler room, that's okay, too. The recommended range is 60–68°, so there is some wiggle room.
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.