The most common causes for an Android phone to get hot and what you can do to prevent it or stop it once it happens

The Avast Guide to Android Apps Part 3 explains what causes Android phones to get so hot and what you can do about it.

Most of us have experienced an overheated cell phone, particularly that radiating warmth after a conversation that went on extra-long. But what are some of the other causes why phones get so hot? Sometimes to the point where it won’t function until it cools down?  In this next segment of The Avast Guide to Android Apps, we look at the most common reasons phones get hot, and tell you what you can do to stop your phone from overheating.

Why do phones get hot?

Unfortunately, there’s no single answer to this question. Sometimes phones get hot as the result of too many apps running in the background. A bad battery or other hardware problems cannot be ruled out. Other times, it’s because of a malware infection.

Here’s the thing: All phones can, and usually will, get a little hot from time to time. But it becomes a problem when your phone heats up to the point where you cannot even hold it, or it begins to exhibit odd behavior. There are a number of reasons why this could happen.

Identifying the culprit

There are some telltale signs you can use to determine why your phone is heating up.

First off, heating can be caused by faulty hardware, but it can also be triggered by software glitches. There are three main areas in a phone that generate heat: the battery, CPU, and screen.

When a phone gets hot, the battery is usually the first place to look. Even more so if the heat is coming from the back of the phone. Modern lithium-ion batteries are extremely powerful, which is why they sometimes get hot. The heat causes the battery to vent its organic solvents which could actually ignite from too much heat or a spark. The infamous Samsung Galaxy S7 explosions were caused by faulty batteries (that’s why they recalled 2.5 million units).

If the heat is coming from the front of the screen, however, it may be due to the phone’s CPU or GPU. Both of these components create heat as a byproduct of operation, so when the processor is in demand, the heat production increases accordingly.

Likewise, if you are noticing heat coming from the bottom of your phone, there is a very good chance there is an issue with the charging unit.

How hot is too hot?

Remember, all phones get hot. But how can you tell if your phone is experiencing a problem? All phones have a normal temperature range of 37-43 degrees Celsius, or 98.6-109.4 degrees Fahrenheit. Since we don’t (yet) have thermometers in our fingers, we have to use our best guess to judge when it might be a good time to stop binging on YouTube videos and let our phone catch its breath.

You can also check out apps such as AIDA64 and Cooling Master, which both work wonders here. While AIDA64 can tell you almost everything you need to know about your phone, Cooling Master is specially designed to detect overheating in phones and stop it by halting the apps that are throttling it. Another cool app is CPU-Z, which is specially designed to detect CPU heating.

Why do phones get hot?

Let’s say you have a phone that is literally too hot to handle. Here are several more reasons why it might be happening:

You’re gaming…a lot!

Come on, don’t tell us you haven’t binged on Clash of Clans or one of the many Tetris knockoffs on your way to work or on a lazy Sunday. Much like PCs, gaming on a smartphone taxes the CPU and GPU to their limits, which causes them to generate a lot of heat. While the occasional gaming session won’t kill your phone, those spanning several hours are not recommended without frequent breaks.

Too many background apps

As you minimize your Gmail app to check out Facebook, you are not actually turning it off. Rather, your Gmail is still active in the background. Ditto that for every app you minimize. The more apps you have running in the background, the harder your system has to work to maintain them. Generally speaking, background apps aren’t typically a problem. However, if you never go into settings and turn them off, they could turn into one.

Binging on streaming videos

Yes, unfortunately, binging on YouTube or Netflix for season-long sessions is just as detrimental to your phone’s health as marathon gaming. Truth be told, anything that keeps your screen lit for long periods of time and uses your phone’s GPU will cause the device to heat up.

You have less-than-optimal settings

Turning the brightness way up, collecting all those widgets and 3D wallpapers, and using the sleep setting for a long session of audio or video are all rather taxing on a phone’s performance. If your phone is heating up, it might be a good idea to dial down the eye-candy and see if that helps.

You left the phone in the sun

Because, well, exposing an object to direct heat means things are going to get hot, period.

App and OS issues

Certain bugs in apps can cause your phone to overheat or misbehave. Same goes for your phone’s OS. Because these apps have to run on different types of devices using different configurations and operating systems, they may act optimally on some, less so on others. The best way to stop them from malfunctioning is to keep them updated.

The biggest challenge of them all: malware

Even though any of the issues above can easily cripple your phone, none of them are as potent as malware. We have already covered all the ways in which malware can damage your phone. Since malicious apps are usually unoptimized pieces of code, they hog your phone’s CPU and memory, throttling them and generating a lot of heat.

Cryptocurrencies like Bitcoin and Ethereum are also on the suspect list. While almost everyone’s heard of them, what few people know is that the sudden onslaught of cryptocurrencies has spawned a dark industry. Mining cryptocurrency takes a lot of processing power, and miners are often torn between the cost required to mine the coins and the market value of the coins themselves.

One of the easier (and more nefarious) ways of mining is cryptojacking, where a hacker takes over a system’s processing power and uses it to mine cryptocurrency without informing the user. Cryptojacking is so popular that it has become an even more potent threat than ransomware.

Cool your phone down

More often than not, the reason your phone heats up is due to a number of different issues, not just one. Here are some tips to help you drop the temperature.

First, never put the phone in the freezer. Suddenly introducing your phone to radically different temperature ranges can cause the screen to crack and the system to experience hardware issues. Similarly, putting a phone in the fridge will cause condensation both in and out of its shell, which can damage electronic components.

Better suggestions include:

Turn off that app 

If you notice your phone heating up after you turn on a certain app, shut it down by first minimizing it, then going to Settings > Apps > Running Apps > [The app you want to shut down] > Touch Stop or Force Stop. 

Remove the case

A skin or phone cover can act as insulation, causing a buildup of heat. Remove it to let the phone cool off. If the problem persists, use the phone without it.

Run the phone on low power

On Android, look for Battery Saver Mode.

Turn off unnecessary settings

Too often, people leave GPS, Bluetooth, or Wi-Fi options turned on, even when they don’t need them. Turning off unneeded apps can end overheating and save battery life. Better still, turn on Airplane Mode when you don’t plan on using your phone.

Get rid of junk

Trash not only the apps you don’t use, but also junk data that useful apps keep collecting as well. Avast Cleanup for Android can help you out here.

Turn the brightness down

Or turn on Adaptive brightness.

Keep your apps up to date

Updating is essentially another name for optimizing. The more optimized an app is, the fewer resources it uses, which translates to less of a likelihood that it will heat up your phone.

Change the charging cable

Every once in a while a faulty charging cable can cause the charging unit to malfunction. If the heat is mostly concentrated around the cable port, then you might consider switching to another cable.

How to prevent overheating in the first place

Start with an antivirus. This is your bouncer at the door, making sure nothing harmful gets in to heat up the place, including cryptojacking malware. A robust cybersecurity software like Avast Free Antivirus blocks the malware on the spot, as well as alerts you if a website you try to visit is infected. Take the step to protect yourself...and your hardware.

Also, keep in mind all of the above advice, especially the commandment not to leave your phone in direct sunlight. Depending on how strongly the sun is beating down, your phone could overheat very quickly (for example, if you leave it on your dashboard in your car). Stay mindful of where you place it so it doesn’t get fried when you’re not looking. If we treat our phones with care, they’ll continue serving us well.