Is it okay to keep AC on fan mode?

Author: Dr. Trey Medhurst  |  Last update: Thursday, February 19, 2026

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.

Is it okay to run AC in fan mode?

No. Don't run fan mode unless you like paying ConEd more money. The cost difference (if any) between running the AC or Fan only is negligible. For temps similar to what we're experiencing now, you're better off with a plug in fan to circulate the air.

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.

Is it OK to keep fan on while AC is on?

Yes it is a good idea to run the ceiling fan with AC on. It will ensure that the cold air circulates quickly in the room and help bring the temperature down quickly. In addition, you might not need to run AC in full blast and low temperature.

Is it better to leave the 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 set my thermostat fan to on or auto

Is it OK to run AC fan all night?

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 expensive to keep the AC 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. At this point, it should be pretty obvious that AUTO costs less than ON but let's math it out to its logical conclusion.

When should I keep my AC fan on?

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.

Does leaving fans on help the AC?

Because ceiling fans help the AC, they also help to reduce energy costs as your AC unit is able to run more efficiently. Each room will have a more even distribution of cool air so that it is more comfortable.

Does putting your AC on fan save money?

The blower fan uses around 500 watts per hour to run. That's a huge difference! This is why running only the fan (regardless of which method you use) to help keep cool can save you significantly on your energy bills. Of course, the fan on its own doesn't have the cooling power of the air conditioner.

Can I run just the fan on my AC?

While it is true that the fan alone uses less energy than the AC, leaving it on will almost certainly result in higher utility bills. Running the fan constantly also increases your system's maintenance needs. That's because the more you run the fan, the faster your filter will get clogged.

How long can AC run continuously?

In general, wall and window air conditioning units with smaller capacities can typically run for up to eight hours at a time before they need to rest. Larger wall and window units have a longer running time of around 10 to 12 hours, depending on their cooling power.

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 bad to leave AC fan on?

You can expect a more considerable maintenance burden if you run the fan continuously, even if you're running the AC fan without cooling. The filter will clog sooner, and the mechanical parts need more frequent attention to avoid breakdowns.

What does fan mode do on an AC?

What does the fan setting on an air conditioner do? It activates the unit's fan to circulate the existing air in the room without engaging the cooling mechanism. This way, it helps in creating a fresh ambiance without significantly altering the room's temperature or humidity levels.

What is the best mode 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.

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.

Does running a fan help with air conditioning?

Yes, as long as your ceiling fan is set to spin in the right direction, it can increase air conditioning efficiency and help reduce how much you spend on your monthly electric bills. Depending on the time of year, you should set your ceiling fan direction to clockwise or counterclockwise.

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 fan on 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 okay to leave the fan on all the time?

A fan's housing will get warm after prolonged use due to the fan's motor generating heat when converting electricity into movement. This heat is why many people think it is unsafe to leave fans running; however, it is normal and will dissipate from the fan's housing and not exceed a safe limit.

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 cheaper to run AC fan only?

However, you might also think that you'll save money by running the fan without the AC when it's warm out. Professional air conditioning repair technicians actually advise against this, however; while it's true that the fan alone uses less energy than the AC, it will almost certainly result in higher utility bills.

Does turning fan AC increase your bill?

A constantly running fan will increase your utility bills and produce more humidity in your home because it will just blow warm air around without the AC absorbing moisture and heat.

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.

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