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

Author: Dr. Benny Murazik  |  Last update: Wednesday, May 21, 2025

"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.

Should I set my Honeywell thermostat to fan or auto?

AUTO is the best option to save on energy bills and maintain the health of your HVAC system.

Is it better to have the thermostat fan on or auto for heat?

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.

What mode should my Honeywell thermostat be on?

Automatic mode sets the thermostat to follow the temperature program. Operating the thermostat in this mode is the best way to maintain a high level of temperature comfort whilst maximising your energy savings.

Should the fan be on an auto or circulate?

Given the amount of money it costs in increased utility bills and filter purchases to keep your AC fan running constantly, most of the time, you'll want to keep the fan in the “auto” position. That said, there are times when it makes sense to keep that fan running.

Should I set my thermostat fan to on or auto

Should I leave my fan on auto or on?

"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 is the difference between circulate and auto on Honeywell?

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.

What is the best setting for fan on Honeywell thermostat?

The Auto position will allow the system fan to operate whenever the heating or cooling system is turned on by the thermostat. The fan will not blow air unless there is a call from the system. This is the normal setting for a system fan.

How to use auto on Honeywell thermostat?

If you want to change the heat set point when it says “auto cool, you must first press the mode button until the mode shows “heat”, then use the + or – to change the heat set-point. Then press the mode button to switch the mode back to Auto Changeover.

What is the best setting for your thermostat?

Energy.gov suggests that 68 degrees is a good room temperature while you're awake at home but recommends lowering it while you're asleep or away. Lowering your thermostat 7-10 degrees for eight hours a day can reduce your annual heating expenses by as much as 10 percent.

Is it bad to leave thermostat fan on?

Leaving the fan running reduces wear and tear on the motor since it's not starting and stopping repeatedly. It's also beneficial to boost filtration, but leaving it on this setting has more drawbacks than benefits. When it runs nonstop, the fan consumes more energy, and the air filter needs frequent replacement.

Should the fan be on auto or on in winter?

When it comes to whether you should set your furnace fan to “on” or to “auto” in winter, the answer for me is “auto” because it's the move that has the most to do with energy efficiency. It is not, however, the only thing you can do this winter to bolster your HVAC system's energy efficiency.

What is circulate mode on a Honeywell thermostat?

Depending on the make and model of your thermostat, there may be a middle ground between auto and on. Some thermostats allowing you to schedule fan runtimes throughout the day, say, 20 minutes each hour between heating or cooling cycles. Honeywell thermostats call this feature “Circ,” short for circulate.

Is it better to have the fan on or auto in the summer?

Say hello to a sweaty, humidity-filled home! 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.

Should I keep my thermostat fan on or auto for 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 cheaper to keep heat on auto or on?

The main benefit of setting the thermostat to 'Auto' is that it will result in more energy efficient usage. This is because the fan will run only when it's required.

What should thermostat be set on auto or on?

If you're looking for more efficient flow, keep your thermostat mode set to “auto” and add ceiling fans to each room to help the air circulate better around the home. This will help keep your energy bill lower and help reduce the amount of energy you're using, which is better for the environment!

How to get Honeywell thermostat to cool?

Locate the system Slider Switch labeled Heat Off Cool. Slide the switch to the desired setting and either manually adjust the arrows to the desired set point and press hold or establish a schedule for heating and cooling.

Why does my Honeywell thermostat keep shutting off?

If the thermostat keeps turning on and off, try replacing the batteries first. Faulty wiring – Loose wires or bad connections can cause intermittent power loss to the thermostat. Compatibility – Newly installed or replacement thermostats that repeatedly reboot may not be compatible with the home's HVAC system.

Which fan setting is the best?

The ceiling fan direction in summer should be counterclockwise to help create a downdraft, which creates that direct, cooling breeze. Your fan direction in winter needs to be clockwise to create an updraft and circulate warm air around the room.

Does Honeywell fan cool the room?

The fan moves the cold air around the room, so you can feel cooler than with the A/C alone.

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.

What is the difference between fan on and auto?

AUTO is short for automatic. The fan only turns on when cooling or heating is required. If you are generally as comfortable in one room of your home as the next, you'll want to use the AUTO setting. The AC fan kicks in when needed and stops running when the job is done.

What does auto do on Honeywell?

System Auto function allows your system to automatically switch from Cooling to Heating depending on the temperature inside the home. Fan auto means that the fan only turn on with a call for cool or heat. If fan is in manual then it will run all of the time.

Is it better to leave AC on auto or off?

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.

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