Why Does Laptop Fan Turn On When Charging?

Most laptops have at least one fan, except some brands’ have fanless models and gaming variants usually have two or more. These laptop fans may turn on when charging and stay quiet whenever you run the device on its battery. So, why do your fans turn on when charging?

Your laptop fans turn on when charging due to a higher frequency and increased power consumption, which generates more heat. If a laptop’s plugged-in system cooling policy is active, the fans might stay on while charging or still have active applications, causing the fan to run.

Laptop fans should turn on whenever the system needs to be cooled, which isn’t necessarily a case of overheating.

An active cooling policy may proactively keep the temperatures in check all the time. The rest of this article will review all the possible reasons your laptop fans turn on when charging.

Why Does Laptop Fan Turn on When Charging?

There are at least 10 reasons that may explain why your laptop fans run while charging, but this list isn’t in any particular order, such as the probability of each issue in your case.

Also, you may have more than one or two elements collectively keeping the laptop fans on when charging.

1. The Laptop Is Operating at a Higher Frequency

Generally, laptop processors don’t operate at peak clock speeds or maximum frequencies when a system runs on battery power.

Most modern processors or CPUs have different throttling mechanisms, such as dynamic frequency scaling, to regulate the clock speed or rate.

It’s important to note that dynamic frequency scaling isn’t the same as throttling necessitated for safety if a CPU is exposed to heat exceeding the maximum thermal junction temperature.

Other internal thermal control mechanisms, such as automatic shutdown, can reduce power usage and temperature.

A laptop running on battery usually prioritizes energy efficiency to reduce power consumption, so it doesn’t have to conserve battery or power when it’s plugged in and charging.

Hence, the CPU speed picks up to improve performance, and it can theoretically reach the maximum frequency.

Any CPU operating at its maximum frequency will generate more heat than at lower clock rates, so a fan or two must turn on to cool the processor when your laptop is charging.

This applies to all laptops with fans, irrespective of the varying CPU specifications, such as:

• Clock speed or frequency in gigahertz (GHz).
• Boost, max, turbo frequency, or similar specs.
• Unlocked processors that support overclocking.

2. Your Plugged-In System Cooling Policy Is Active

Laptops running Windows usually have two cooling policies in the power settings: active and passive.

Both options are available for customized profiles and the standard mode, such as the balanced plan, which is typically the default or recommended power setting.

If your system cooling policy is active for the plugged-in phase, the laptop fans will likely turn on as soon as you start charging the device.

Since the default mode is active, you must alter the system cooling policy to passive if you don’t want the fans to turn on immediately.

The path to changing this setting may vary among Windows versions. Nonetheless, you can use these sequential steps as a general guide:

1. Go to Windows Settings.
2. Check Power and Sleep.
3. Go to Additional Power Settings.
4. Selected Plan, i.e., Balanced.
5. Change Plan Settings.
6. Change Advanced Power Settings.
7. Processor Power Management.
8. System Cooling Policy.
9. On Battery and Plugged In.
10. Choose Passive for Plugged In.

I must mention here that passive cooling may throttle the clock speed or processor frequency if the system has to reduce power consumption.

This throttling may impair a laptop’s performance. On the flip side, active cooling uses more power so that the fans may stay on throughout charging.

3. The Higher Power Consumption Is Generating More Heat

A plugged-in and charging laptop draws power to charge the battery and run the system simultaneously.

Hence, your power consumption is greater than what a fully charged laptop will draw for a few apps you may have open and essential system processes.

Laptops can draw much less than 50 W to over 100 W depending on several features, such as the following:

• Hardware specs.
• Processor speed.
• Running programs.
• Screen size and type.

Suppose the laptop is drawing 100 watts for all the processes your system is running, and the battery is drawing an additional 10 to 20 watts of power, subject to its size.

In such a scenario, the net power consumption is 110 to 120 watts, which is sufficient to generate significant heat. 

The cooling fans must turn on and continue running until the laptop draws less power, which may be once the battery is charged or after you close a few demanding apps or processes.

An idle laptop with its display off can also be a suitable option to reduce power consumption.

4. You Have Many Active Processes and Applications

Running too many applications or even keeping them open can overwork or stress a system. As a result, your laptop may draw more power than it has to while charging.

Background processes have a similar effect on your laptop’s power consumption.

Contemporary operating systems, especially Windows, tend to run plenty of applications in the background, whether or not you actively use them at any given time.

You must close all these background applications and other non-essential processes if the system draws a lot of power.

Any laptop drawing closer to its maximum wattage constantly will get overheated, so the fans will turn on and continue running.

This problem will likely worsen while charging because the laptop will also draw power to charge the battery, and there’s already a spike.

You can close all background apps or select those that you want to keep running. The path may vary among Windows versions, but the first two steps are Start and Settings.

Subsequently, you may have to check your Privacy settings or go to Apps and then More Options. 

5. Your System Is at Its Highest Performance Setting

If the system is running at its highest performance setting, your laptop will likely overheat, and more so when you plug it in to charge the battery.

The higher wattage for the battery and to run the laptop will combine with the highest performance prerequisite to worsen matters.

Suppose you have a 3.5 GHz processor, which can operate up to 3.5 billion cycles per second. That requires billions of transistors in the processor to continuously open and close in real time.

Such peak performance settings will draw much more power than an energy-saver mode.

As a result, the fans will turn on. The highest performance setting may also turn on the fans if a laptop is running on battery, as laptops don’t always overheat only when you charge them.

Peak performance can lead to some thermal zones exceeding the maximum junction temperature.

Those overclocking their CPUs or running their laptops at peak processing power may already be familiar with fans turning on and running continuously.

The processor’s max clock speed or overclocked frequency heats the system. Hence, the fans must cool the hardware.

Consider reviewing your performance setting. Some laptops allow users to access and toggle the performance setting by clicking on the battery icon on the taskbar.

You can move the slider to the left to reduce the peak frequency of your laptop processor. 

If you have overclocked your laptop, consider disabling overclocking to check whether or not that was the triggering factor.

6. The Laptop May Be Dusty, or Its Vents Are Blocked

I’ve already discussed various internal and systemic causes of laptop overheating.

However, a laptop may also overheat due to a dusty chassis. Suppose you have a passive cooling policy for the plugged-in phase, and no demanding apps are running, but the fans still turn on while charging.

In such scenarios, the laptop may have a heat island inside the chassis if it can’t cool naturally, which is often due to dust buildup inside the case.

The fan will turn on to try and cool the laptop, and it may spin continuously and even faster if it still can’t reduce the temperature.

A similar problem is likely if your laptop’s vents are blocked. Dust or debris isn’t the only issue in this context.

A laptop placed on an inappropriate material or surface may also struggle to have the required airflow for the vents to dissipate heat. A few examples are:

• Beds.
• Carpets.
• Fabrics.
• Pillows.

There should be some clearance between the laptop and the surface you keep it on.

A glass, wooden table, or another material that doesn’t prevent heat dissipation and ventilation are ideal.

If you have clogged vents or a dusty fan, you should clean them to prevent overheating.

7. You Have a Dusty Heatsink and Dry/Worn-Out Thermal Paste

Suppose you don’t have a dusty fan or clogged vent, and none of the issues I’ve discussed in this guide until now is a problem.

In such a scenario, check your laptop CPU’s heatsink and thermal paste.

A dusty heatsink is likely to be inefficient. Similarly, if the thermal paste has dried or worn out, it’ll fail to effectively transfer heat from the processor to the heatsink.

Both or either can cause a laptop to overheat, especially when charging, and the fans will turn on to cool the system.

You need to clean the heatsink and ensure it’s aligned correctly. If the thermal paste is dry and worn out, you must replenish it to keep the CPU cool.

However, note that these solutions don’t override the active cooling policy for a plugged-in laptop and other issues I’ve explained above.

8. The Peripherals Are Consuming a Lot of Power

If your laptop is connected to a few peripherals, their collective power consumption may spike the watts drawn, which can overheat the system.

Thus, your laptop’s cooling fans may turn on while charging. Such an issue is more likely with battery-charging and power-delivery ports.

The older USB ports draw around 2.5 W to 4.5 W, depending on the standard. A battery charging port of the same generation can draw up to 7.5 W.

In contrast, the faster and more powerful USB ports can draw 15 W (regular) to 240 W (power delivery).

Even if your laptop has a few older ports, the combined watts can be a significant spike if all are connected to peripherals drawing some power.

The more recent ports are power-intensive, and they can definitely cause an enormous increase in the watts drawn by your laptop.

Review the peripheral connections and determine whether they’re devices being charged or just an external hard drive that you’re using while your laptop is charging.

9. Certain Programs Are Spiking the Laptop’s Wattage

While plenty of active processes and background apps can overwhelm the CPU and RAM of a laptop, most don’t draw a lot of power individually.

But some programs can lead to a massive surge, such as a memory system process of Intel that’s poised to be discontinued.

Some programs can singularly draw enough power to overheat a laptop, even if you close all other background apps and shut down major processes.

Look for such programs, and consider ending these processes using the Task Manager.

10. Your Laptop May Have Defective Hardware

Like desktops, laptops have plenty of hardware components dedicated to distinct tasks. Some of these parts can overheat and also trigger the formation of thermal zones, including but not limited to the following:

• Mainboard.
• Capacitors.
• Transistors.
• MOSFETs.

If these and other components overheat, the laptop fans will turn on, which is more likely when it’s charging due to the excess power draw.

Connected peripherals drawing power can make this problem worse. A super hot laptop may have permanently damaged hardware components.

The other issue, albeit less common, is using incompatible hardware for your laptop, including the adapter/charger, whether it’s a standard one or a fast-charging variety.

Manufacturers don’t use identical AC adapters to charge different laptop models. Dell has AC adapters ranging from 45 W to 240 W.

However, don’t use a more powerful AC adapter to charge an incompatible laptop.

Likewise, don’t use an incompatible battery for any laptop, whether it’s Dell or any other brand. Such incompatibility issues don’t eliminate the other possibilities.

You may have multiple triggering factors whenever your laptop fans turn on while charging.

Conclusion

It’s normal for laptop fans to turn on when charging.

If the noise is a problem or you suspect the system is overheating, it’s best to investigate the issues I’ve highlighted here.

You may start looking into the simplest causes on this list or what you suspect is the trigger and proceed accordingly.