If your air conditioner is set to 75 degrees, it will take a few minutes to shut off on the “Cool” and “Auto” fan settings.
Air conditioners use signals from temperature sensors and thermostats to determine whether the air in your room has reached the desired temperature. It may take a while for your air conditioner to shut off once it has reached 75 degrees if it is on the correct settings.
If your air conditioner does not shut off, this may be because you are hearing the fan, the unit is the incorrect capacity, or because of the outside temperature.
How do air conditioners sense the temperature of your room?
Air conditioners are widely regarded as convenient appliances because they allow you to select a desired temperature that you want the air in your room to be.
The air conditioner senses when the air in the room reaches this set temperature and then switches off until the room gets too hot again.
The main ways that air conditioners sense whether the air in your room has reached this desired temperature is through a return air temperature sensor, an indoor unit room temperature sensor, or through a thermostat.
If an air conditioner is set at 75 degrees, what must it be to shut off?
Given that an air conditioner uses this feedback-loop to determine when your room has reached the desired temperature, which, in this case, is 75 degrees, there are a few factors you should take into account about how and when it will shut off.
The first point is that your air conditioner will not shut off immediately when the room reaches 75 degrees if this is your desired temperature.
Air conditioners may continue to run for 15 to 20 minutes after your room has cooled down and you can time this using a thermometer to determine when your room reaches the desired temperature and a stopwatch to determine how long it takes for the air conditioner to turn off.
This way, you will know whether your air conditioner is cycling on and off normally when it reaches your desired temperature, or whether there is something wrong with the way it operates.
The second point to consider is if your air conditioner is set to 75 degrees but it is not shutting off for over 20 minutes after the room has reached the set temperature.
If this does not fix your problem, there are many other factors to consider, such as the capacity of your air conditioner and the 20-degree rule.
Considering whether your compressor is running
If your room has reached 75 degrees but it seems that your air conditioner is not shutting off, you may be hearing the fan and the fan motor instead of the compressor.
When the fan is set to “On” it will run continuously, whether your air conditioner’s compressor is operating or not and this could make it sound like the air conditioner is working when it is not.
Considering the capacity of your air conditioner
If your air conditioner is set correctly but is still not switching off when the temperature is set to 75 degrees, your air conditioner capacity may be the problem.
In other words, your air conditioner may not have the capacity to cool your room to the desired 75 degrees and it will keep working because the temperature sensor will never signal that it should turn off.
You can verify this by placing your thermometer in different spaces in the room to determine whether the room has actually reached 75 degrees.
If it has not, you need to ensure that the size of your room is compatible with the manufacturer’s stipulations for your air conditioner’s cooling capacity.
Consider the 20-degree rule
In much the same vein, your air conditioner will not be able to shut off if the temperature of the air is too high to get it down to the desired 75 degrees.
Experts advise that your desired air conditioner temperature should never be set to more than 20 degrees lower than the outside temperature in order for your air conditioner to work as effectively as it should.
If you really want to try to get your room down to 75 degrees when it is hotter than 95 degrees outside, you need to insulate your room properly with weather stripping and insulation foam to ensure that none of the hot outside air gets inside.