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. A frozen air conditioner may subsequently result in higher repair bills and even higher electricity bills.
The problem with running a standard AC at such low temps is that once the evaporator is below 32F it'll begin to form ice and there is no mechanism in place to allow a defrost. Refrigerators are all outfitted with defrost timers and they will periodically shut down the compressor and melt any ice that formed.
In most cases, air conditioners only have one speed (though some have variable speed settings to improve energy efficiency). Lowering the temperature too much causes your air conditioner to operate longer, causing more wear and tear on it as well as higher utility bills.
Air conditioners have minimal temperature limits below which a person will begin to feel uneasy. Each air conditioner, regardless of model or brand, has the lowest temperature limit. The temperature must be below 60 degrees Fahrenheit. The unit's inner coils will freeze.
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.
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.
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.
Air conditioners are graduated to run within an ideal set of temperature thresholds. If you are operating your AC when the outdoor air is below 60 degrees, then the air pressure inside your unit will fall, and this can cause your Central Air Conditioner to freeze up.
You need your air conditioner to keep your home comfortable during the hottest months, but when the temperature is at its peak, you need to be careful. If you set the thermostat too low, it strains the AC. This leads to air conditioning malfunctions and costly repairs.
LOW REFRIGERANT
Improper refrigerant fluid levels can also cause an HVAC unit to freeze up. When the refrigerant is low, the coils will be too cold, causing them to freeze. You can hire air conditioning service and repair to check your refrigerant levels and replace them, if necessary.
Quick answer: The ideal house temperature is room temperature, which ranges from 68 to 78 degrees F, though this may vary from season to season.
When the AC temperature is too low, between 60-67 degrees F (15-19 degrees C), the evaporator coil inside the unit can get excessively cold. If the humidity in the room is high, condensation can accumulate on the coil, which may lead to the formation of frost or ice.
Most experts maintain that running your AC below 70 degrees can cause issues with your unit, including the risk of freezing the evaporator coil. It's worth noting this low setting would also quickly run up your energy bill.
1st Step: Turn Your HVAC Unit Off.
Even if it's sweltering outside, you still need to turn OFF your air conditioner! Running a frozen air conditioner will wear out parts much faster, and could overheat your unit. Worn parts are bad news for the most expensive piece of your HVAC unit—the compressor.
IS 68 TOO COLD FOR AC? Setting your AC to 68°F might feel too cold for some, especially in residential settings, as it is lower than the typical comfort range. However, preferences vary, and this temperature might be suitable for those who prefer cooler environments.
An AC unit is happiest creating space temperatures no lower than 68 degrees fahrenheit.
For example, HVAC specialists recommend setting your thermostat no lower than 20 degrees the outside temperature. Suppose the outdoor temperature in your area is a blistering 90 degrees Fahrenheit. It's probably best to keep your thermostat between 70 and 80 degrees Fahrenheit to prevent stress on your unit.
This sounds unbelievable, but it does happen, especially in higher altitudes. This is why many HVAC experts say you shouldn't lower your thermostat below 72 degrees during warm months or below 78 degrees in the hot months.
Do not set your thermostat below 70 degrees as it will not cool any faster and could freeze up the system causing more problems. Understand that there is generally a 20 degree difference between indoor air and outside temperatures.
If the thermostat malfunctions and detects the wrong temperature, this can cause your A/C to run too hard for long periods of time. If your A/C runs for too long it can cause the coils to freeze.
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.
Dirty air filter: A dirty air filter can restrict airflow, which can make it harder for your AC unit to cool your home. If your air filter is dirty, it's recommended to replace it every 1-3 months. Low refrigerant: Refrigerant is a liquid that helps your AC unit transfer heat from inside your home to the outside.
Using Your AC When It's Too Cold Outside
Lastly, if the temperature outside is below 60 degrees, and your AC's temperature is set below 68 degrees, this can cause the evaporator coils to freeze as there is not enough warm air in the house for the AC to sufficiently cool.
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.
The recommended rule of thumb for summertime is to set the temperature to 78 degrees Fahrenheit when you're home and higher when you're away. In general, set it to 82 degrees Fahrenheit when you're asleep and 85 degrees Fahrenheit when you're away.