Should the outside fan run when AC is on?

Author: Ms. Margot Thompson MD  |  Last update: Sunday, September 28, 2025

Does The AC Fan Outside Always Run? The answer to this is no. The AC fan does not run non-stop. It's intended to cycle on and off, depending on the needs of the HVAC unit.

Should the outside fan always run when AC is on?

Yes, you want the fan to run anytime the A/C is on. That is how the cold air gets blown into the space. Many A/C systems will kick the fan on automatically, but not all A/C systems will do this. Therefore, it is always best to have the system fan on whenever the A/C is on.

Why is the outside fan not running on my AC unit?

The main reason your AC unit fan isn't spinning could be a lack of power to the fan or an obstruction. The other potential issues are the fan isn't getting enough voltage, the fan motor is too hot, something is stuck in the fan blades, or the fan belt needs to be replaced.

Should the fan be on while the AC is on?

This means, that in turn, when your setting is turned on auto less electricity is used. When your fan and air conditioner are running all the time, more electricity is produced. All in all, it is better to leave your air conditioner's fan on auto, instead of “On” at all times.

Why does the outside AC fan keep running?

Restricted Airflow

If there's not enough air circulating, your AC will be ineffective at cooling your home. It can also overwork itself and reduce energy efficiency. Since the system can't cool things off, the outside fan may run constantly.

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Why won't my outside AC fan turn off?

If your air conditioning system won't turn off, there are most likely malfunctioning mechanisms, such as a faulty thermostat or fan limit switch, frozen evaporator coils, electrical issues, or incorrect thermostat or fan speed settings.

Should the fan be spinning on an AC unit?

The outside AC fan also plays a significant part, blowing air over warmed refrigerant to get rid of heat and cool the system back down. An AC fan not spinning means your home's HVAC system won't be able to do its job correctly.

Why should we not use fan while using AC?

It only makes you FEEL cooler because it's moving air over your skin, carrying the heat away from your body. This is the wind chill factor you hear on the Weather Channel so often. So it's doing nothing to lower the temperature in your home, meaning your A/C will run just as long whether the fan is on or not.

Is it better to leave AC on auto or fan?

Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.

How often should fan run on AC?

Your blower motor circulates air through the furnace and can provide uniform temperatures. Many people leave their HVAC fan on all day, while others opt for two to three cycles per hour, ranging from ten to 25 minutes, depending on how close to heating or cooling temperatures they are.

Can AC work without outside fan?

Air conditioning without an outdoor unit is called water cooled air conditioning, because it uses mains water to cool down the internal refrigerant, rather than outside air. This allows the system to be fully internal, as all of its components are located within the property.

How do I reset my outside AC fan?

In AC systems, the air conditioner reset button is on the outside unit's lower edge, typically close to the ground. Some models have the reset button located behind the service panel, which may require tools to remove. Reset buttons are usually red or yellow with a clear “reset” label.

How do I know if my outside AC fan motor is bad?

7 Signs Your AC Fan Motor Is Failing
  1. The Fan Won't Come On. A sure sign of a bad fan motor is a cooling fan that will not come on. ...
  2. The Fan Blades Rotate Slowly. ...
  3. The Condensor Makes a Rattling Noise. ...
  4. The Fan Runs Intermittently. ...
  5. Fan Runs When Unit Is Off. ...
  6. You Smell Burning Smells. ...
  7. Frequently Tripped Breakers.

What is the purpose of the fan on the outside AC unit?

The outdoor unit also has a fan that pulls air through the outdoor coil. This process allows the system to release heat that has been absorbed from inside the home. Central, split-system, ductless, and packaged air conditioners all use fans.

Why is AC not blowing cold air?

First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.

Do we need to turn on fan when AC is on?

Positioning your fan so that it is near the A/C vent helps distribute cold air faster and more efficiently than the A/C alone could. This helps circulating air for a larger area and cool the room quickly. By using the fan, the Ac need not be on a very cold setting which costs more money.

Should the fan be running when AC is on?

It might be helpful to know that using the ceiling fan while the AC is running can actually help you save energy and money. By setting your thermostat up to 4 degrees higher while the ceiling fan is on, which helps to reduce the cost of running your unit, you can save up to 17 cents per hour.

What temperature to set an air conditioner in summer?

To What Temperature Should I Set My Air Conditioner In the Summer? According to the U.S. Department of Energy (DOE), the recommended temperature setting for your home in summer is 78 degrees Fahrenheit.

Should my AC fan be on auto or circulate?

Energy-Efficiency

Most modern HVAC systems have motors that cost about the same as a 40-watt light bulb when you leave the fan in the 'on' setting. 'Auto' is the typical setting that the air conditioner is set to which is actually more energy-efficient because it only runs when it needs to.

Is it OK to leave fan running on AC unit?

Keeping the fan on creates a more even distribution of heating and cooling, circulating the air if you have cold or hot spots in your house, like a bedroom above a garage. Less frequent starts and stops of the fan can reduce the stress from startup, and potentially help extend it's lifespan.

What fan speed is best for cooling AC?

For your AC system to cool efficiently, the fan needs to be able to move a certain amount of air every minute. For every AC ton, you need between 350 to 400 cubic feet of air per minute (CFM), i.e. a 2.5-ton AC needs 875 to 1,000 CFM, a 5-ton AC needs 1,750 to 2,000 CFM, etc.

When should you not use a fan?

When indoor air temperatures are hotter than about 95 °F: Fan use may cause your body to gain heat instead of lose it. On very hot, humid days, sweat evaporates off the skin slower than normal, and fans make it even more difficult for the body to lose heat by sweating.

Is the outside unit supposed to run when the AC is on?

No, most outside units have a timer where the compressor waits for 5 minutes before coming on. It gives the refrigerant time to equalize so the compressor doesn't have to work as hard to start up.

Should you have the fan and AC on at the same time?

But is it beneficial to use your AC with your ceiling fan? Or are you just wasting energy? In short, you can run the air conditioner and fan at the same time. In fact, you should.

Why is the fan on my outside AC unit not running?

In short, common issues that can cause an air conditioning unit fan to stop spinning are electrical issues, problems with the capacitor, contactor issues, a burnt out air conditioner motor, a broken fan belt, or clogged air filter.

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