Is it better to keep your AC fan on auto or on?

Author: Adolfo Kerluke  |  Last update: Monday, April 28, 2025

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.

Should I set my AC fan to on or auto?

"AUTO" is the more energy-efficient option, as it runs the fan only when heating or cooling is actively needed. "ON" keeps the fan running continuously, which can help with air circulation and filtration but may consume more energy.

What are the disadvantages of auto mode in AC?

AUTO Setting Disadvantages
  • Hot and Cold Spots. The air distribution throughout the house may be uneven, leaving some areas colder than others. ...
  • Limited Air Circulation. ...
  • Blower Fan Wear and Tear.

Is it OK to leave AC fan on all the time?

They should not be left on all the time. Some of the more advanced thermostats might use the fan to better circulate the air post-AC or heat running or pre-cool the home a little by running the fan. But in normal operation, it only runs with the furnace or AC does.

Should I keep my HVAC fan on my auto?

Pros for “Auto”: If you set your furnace fan to “auto,” the fan will only run when the system tells it to in order to keep your home as warm as you want it based on your thermostat settings. This means it's consuming less energy than when it runs non-stop, which means lower furnace bills.

Should I set my thermostat fan to on or auto

Which mode is best for AC cool or auto?

Auto mode is ideal for homeowners who want to maintain a consistent temperature in their homes without having to constantly adjust the settings.

Is it expensive to keep HVAC fan on?

Therefore, the fan uses about 360 kWh per month in the ON mode. The average kWh in the US costs about $0.12 so it costs about $43 per month, or about $520 per year, to run a fan continuously.

Is it better to run HVAC fan continuously?

This approach can reduce wear and tear on the air conditioning equipment because the fan doesn't have to start and stop as often. Running the fan on the AC all the time also helps maintain a more consistent and even temperature throughout your home because air is constantly circulating, eliminating hot and cold spots.

Is it OK to keep AC on fan mode?

Yes, it is perfectly fine to keep your AC in fan mode. This setting allows the fan to run continuously, circulating air without using the compressor to cool it. This can be particularly useful during mild weather or when you want to save energy by not cooling the air but still need some air movement.

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.

Should the fan be on when AC is running?

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 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.

Is auto the best setting for AC?

In Summary. We recommend setting your thermostat to AUTO for the best balance of energy efficiency and comfort. If you are concerned about indoor air quality or suffer from allergies, the ON setting's increased air filtration could be beneficial.

Does it cost more to have AC on auto or on?

Choosing the Auto Setting

If you set your preferred temperature very low, your air conditioner is still going to run longer than necessary. But using the AUTO setting with a reasonable set temperature will keep your energy costs low, especially if you turn your unit off when you're away from home or asleep.

Why is my AC constantly running on auto?

The Short Answer Is: When your air conditioning system keeps running and never seems to shut off, the problem could be linked to a number of malfunctioning components – frozen evaporator coils, a clogged air filter, a bad electrical relay switch that needs to be replaced, the fan blowing constantly, dirty condenser ...

Does leaving an AC fan on increase humidity?

Leaving your AC fan set to ON allows the moisture in your home to accumulate and reach mold-growing levels of humidity. To ensure that you and your family stay cool and healthy this summer, keep your AC thermostat fan setting to AUTO.

Is it better to leave AC fan on or auto?

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.

Should I run my AC fan on auto or circulate?

Setting your thermostat to auto will allow your system to be more energy-efficient since the fan only runs when the system cycles on, not continuously.

Which mode is best for AC to save electricity?

Eco or energy-saving mode

This is the ideal mode for users looking to save up on energy bills by toning down the performance of the AC and its compressor. Eco-mode uses less electricity by automatically adjusting the fan speed and temperature, while still maintaining a comfortable level of cooling.

Should you leave your AC fan on all the time?

The primary benefit of running your HVAC fan consistently: Air circulation improvements. Running the fan more often means air in your home circulates faster, leading to everything from more even temperature distribution to faster heating or cooling.

Is it expensive to run AC fan all day?

Cons to Keeping Fan Continuously Running:

It could cost you hundreds of dollars a year. The average unit has a 500 watt fan, which uses almost as much energy over the course of the year as a refrigerator, resulting in a $50/month bill.

Is it okay to leave the AC on 24/7?

Consequences of Running Your Air Conditioner 24 Hours a Day

Wasted energy: Running the AC to cool your home beyond your comfort level wastes energy and contributes to an increased carbon footprint. This is bad news for the environment and your energy bills.

Is it OK to run HVAC fan only?

The AC uses less energy in fan mode than when cooling. But running the fan all the time can increase the amount of maintenance your HVAC system might need.

Does auto mode in AC save electricity?

Yes, Auto mode is intended to save energy. The air conditioner can conserve energy and save you money on your energy bills by automatically adjusting the temperature and fan speed based on the ambient conditions and the presence of people in the room.

Does leaving your AC fan on save money?

Saving money is one of the most obvious reasons to not keep the air conditioner fan on all the time. As you've probably guessed, when it's continuously in operation, it uses up a lot of energy. As a result, you could pay hundreds of dollars more in energy bills each year than you otherwise would.

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