Reduced efficiency: The hotter it is outside, the less efficient your AC becomes. This translates to higher energy bills. Increased wear and tear: Running your air conditioner constantly in high heat can shorten the lifespan of your AC unit by causing it to work harder.
Your air conditioner isn't designed for extreme heat. Tips to keep cool Extreme temperatures present a significant challenge to AC systems, which engineers and installers say are really only designed to keep indoor temperatures about 20 degrees cooler than outside.
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.
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 first issue it can indicate is low coolant in the system. The second issue is the restriction of airflow. An AC system needs enough coolant in it and proper airflow for it to run efficiently and accurately. These are two common reasons that cause systems to stop working.
It is possible for it to be too hot for an air conditioner to work. When the temperature outside reaches a certain point, the AC unit will shut down in order to prevent damage. So, if it's a particularly hot day and your AC stops working, don't panic! It's just doing its job.
Leaking or Low Refrigerant
The most likely cause of this is a leak. A leak not only keeps the AC unit from cooling properly, but also it can cause other issues within the home. For example, when it isn't cool enough, humidity levels can rise in your home making it feel hotter than it is inside.
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.
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.
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.
But you shouldn't run your AC if the temperature is below 60°F. Heat pumps: Modern heat pumps are effective at around 25 to 30°F. Ductless mini-splits: Avoid using the cooling function when temperatures fall below 60°F.
Signs of a Faulty Thermostat
AC Refuses to Start or Stops Suddenly: A thermostat that's not working correctly might fail to initiate the cooling cycle or might randomly shut off the AC. This erratic behavior can be due to electrical issues or miscommunication with the AC unit.
The first thing you should know is that your system is typically not designed for 100º heat. HVAC systems are designed for an average temperature in your area. Your system is also designed to cool to a maximum of 20º below the temperature outside.
One possible reason your AC is not reaching the set temperature is that the thermostat could be dirty. If dirt, dust, or other debris has accumulated within the thermostat box, it can cause the wires to heat up or other issues. Thermostats are cleaned during routine HVAC maintenance to help prevent this from happening.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
Dirt, dust mites, pet dander, debris, and other buildup can get trapped in your AC filter. Once this buildup reaches a certain point, it reduces your air conditioner's efficiency. This makes the unit work harder to cool down your home, which is why it takes longer to reach the desired temperature.
Sleep experts believe the best temperature for great sleep is between 68-72 degrees Fahrenheit. But in addition to making you uncomfortable and interfering with healthy sleep patterns, being too hot at any time of day or night can cause health risks like dehydration and heat stroke.
There are benefits to having your air conditioner set to “auto” and “on.” The benefits of the “auto” setting include higher efficiency, lower energy bills, better humidity control, less wear and tear on some components, and quieter running.
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.
For instance, if it's 100 degrees outside, aim to set your thermostat to at least 80 degrees. Adhering to the 20-degree rule maintains energy efficiency, prevents strain on your cooling system, extends its lifespan, and promotes lower energy bills and consistent indoor comfort.
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.
How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
Yes, you should turn off your AC if it's not cooling.