Is it better to leave the AC fan on or auto?

Author: Alivia Brekke  |  Last update: Thursday, February 12, 2026

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.

Is it better to run AC on fan or auto?

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.

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 the AC fan be on auto or circulate?

Auto = The fan turns on whenever the heat or AC is on. Fan = The fan is always on. The heat or AC cannot not turn on. Circulate = The fan is always on.

Is it good to keep AC in auto mode?

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.

Should my thermostat fan be on auto or on?

Should I leave AC on cool or auto?

As we stated in a few sections above, it's very important to keep your air conditioner's fan on the auto setting. Some of the reasons behind this choice include: Lowered energy consumption: When your air conditioner's fan is set on auto, it will only run as needed.

Which mode is best for AC in summer?

WHAT IS THE BEST MODE FOR AC IN SUMMER? In summer, the best mode for your air conditioner is the "Cool" mode, set to a comfortable temperature around 78°F when you're home. This setting efficiently reduces indoor humidity and maintains a comfortable environment without overworking the AC system.

Should I run the fan on my AC continuously?

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.

What does the fan setting on my AC do?

What is AC Fan Mode? Essentially, your air conditioner unit's fan mode controls the blower fan. You can choose to run the fan continuously or only when the AC is on. This setting helps circulate air in your home, but it won't produce any new cold air.

What is the difference between Circ and auto fan on a Honeywell thermostat?

Auto: Fan runs only when the heating or cooling system is on. On: Fan is always on. Circ: Fan runs randomly about 33% of the time. *The circulate option that allows you to set the fan to run a certain amount of time per hour.

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 OK for your AC to run all day?

The constant running will reduce pressure in the cooling coil until it freezes over, which is dangerous as it can cause liquid refrigerant to flood back to the compressor and damage it (the compressor is a very expensive part).

Does leaving the AC fan on use a lot of electricity?

A typical AC fan motor uses about 500 watts when it's running. Therefore, if you run the fan continuously for a 30-day month (720 hours), you would use 360,000 watt hours (720 x 500) or 360 kilowatt hours (kWh). Therefore, the fan uses about 360 kWh per month in the ON mode.

Should I keep my HVAC fan on 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.

Is it more efficient to leave AC fan on?

For all the upsides of a constantly running fan, there are some downsides. The most significant is the increase in energy usage and the subsequent higher bills. When you're trying to cut expenses, keeping the AC fan on 24/7 isn't helpful and will probably cost you more.

Should I set my thermostat to auto or cool?

Keeping your thermostat in the AUTO position means less overall energy is being used—and that reduces your utility bills considerably. Not only that, your air filter will last longer than they will if you leave your fan running continuously—in other words, if you leave it in the “on” position.

Should my AC fan be on auto or on?

AUTO is significantly more energy efficient between the two modes since the fan is only running when your AC is going through its cooling cycle. This takes less power, which is more budget-friendly, with some estimates showing you can save as much as $50 per month just by keeping your AC on AUTO.

Is it OK to run AC in fan mode?

You should run the fan on your air conditioner during cooler parts of the day or when the temperature is not too high. It's also useful when you want to circulate already-cooled air or when the room feels stuffy. Using the fan mode can help save energy as it consumes less power than the cooling mode.

What happens when AC fan is on?

The purpose of the fans on your AC system is to circulate the air throughout the rooms in your home. That means all your rooms stay cool and comfortable, no matter what the conditions outside each of your windows. In most AC systems, the fans will have two settings – Auto and On.

Can I leave my AC fan on all day?

The fan will constantly blow air into your room if you have the thermostat turned “ON.” If it is on “AUTO,” it will only turn the fan on when heated air needs distribution. So yes, running HVAC continuously throughout the day and night is perfectly safe!

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.

Can I run just the fan on my AC?

You can run the fan independently of the AC by switching the fan to “Fan On,” which will keep the blower fan running whether there's a demand for cooling or not. The AC can still come on, but you'll have continuous air circulation when it's not. You can also shut the AC off completely so only the fan runs.

Is auto mode good for AC?

Benefits of Auto Mode

When using auto mode, the AC unit will only turn on when needed rather than running continuously like with manual mode. This will provide consistent comfort, reduce your energy consumption, save you money on your monthly energy bills and extend your AC's life-span.

Is 72 a good temperature for air conditioning?

This is more of a personal question, as different people feel comfortable at different temperatures. Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.

What is the best fan setting for AC in summer?

Not only that, but the blower is also running up your energy bill. So, when it doubt, leave your thermostat's fan setting to AUTO.

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