Does the onboard WiFi performance of a Raspberry Pi 4 suffer using a metal Flirc case?

The original plastic Raspberry Pi case is cheap and does its job. But if you want something nicer looking, which at the same time reduces the temperature of your CPU by up to 20 degrees, then it’s time to look at the Flirc cases.

But I was wondering: Doesn’t the metal enclosure impact the onboard WiFi performance? I was in for a big surprise.

Why the Flirc case is so interesting

In the past, my digital picture frame projects used the Raspberry Pi 3. As image viewers don’t require a lot of processing power, the CPU hardly went beyond 10% utilization. This meant that even in hot summers, the Pi 3’s temperature never exceeded 60°C (140°F) degrees in the little plastic case.

But when I started experimenting with the Raspberry Pi 4 model and 4K displays, the temperature went up to 80°C (176°F) degrees. Through a firmware update, the Raspberry Pi foundation was able to reduce it somewhat but the case still got quite hot especially in warmer surroundings.

The dynamic Raspberry Pi community immediately came up with solutions like fans in all sizes and ludicrous monster heatsinks. But for a digital picture frame, the only acceptable solution is passive cooling. Luckily I found the Flirc case.

The Flirc case offers an ingenious way to keep the Pi 4 CPU up to 20°C (68°F) degrees cooler using the entire aluminum case as a heatsink.

This means that there is no CPU throttling and no fan noise.

This was proven by the guy with the Swiss accent, Andreas Spiess, in one of his entertaining videos. When it comes to testing electronics thoroughly, nothing beats his unbiased and dry approach. As a matter of fact, before his experiment, he was not all convinced that the Flirc case would reduce CPU temperature.

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I would strongly recommend to anyone who is building a 4K digital picture frame to use the Flirc case to keep the Raspberry Pi 4 cool even during hot summers. And there may be more of those in the future.

A few variations of the Flirc case have come up by competitors but I find Flirc still the best value for money deal out there.

By the way, the Flirc case is also available for the Raspberry Pi 3 and even the Pi Zero. While you may not need it so urgently to keep the Raspberry Pi cool, it still looks so much better than the standard plastic case. And at around US$16, it is even quite affordable.

But doesn’t WiFi performance suffer in a metal box?

But there was one question that I couldn’t find answered anywhere? Wouldn’t the onboard WiFi performance suffer when the Raspberry Pi was put in a metal casing?

So I decided to find out for myself.

I took my Raspberry Pi 4 with 4GB and put it in a Flirc case and installed the network monitoring software wavemon with

sudo apt install wavemon -y

I started the program with


Onboard WiFi performance test results

I then took the Raspberry Pi completely out of the Flirc case and ran the same test again without any case.

The first position was about 5m away from the WiFi access point.

WiFi Performance Flirc Case Position 1
WiFi Performance No Case Position 1

I was very surprised to see that the Flirc encapsuled Raspberry Pi showed a link quality of 100%, compared to 96% of the “naked” Pi.

Then I moved into another room, about 12m away from the WiFi access point.

WiFi Performance Flirc Case Position 2
WiFi Performance No Case Position 2

Again, the WiFi performance of the Flirc case showed a higher link quality (74%), compared to 66% of the “naked” Pi 4.

This was something I didn’t expect at all. I actually repeated the testing to make sure that I hadn’t mixed up the screenshots but the result was the same.

So the answer to if there is any reduction in WiFi quality when the Raspberry Pi 4 is put into the Flirc case, is clear: on the contrary! The signal is even stronger! Maybe one of my readers with a physics or engineering background can help me understand why this is!

A final tip that can save you a lot of headaches

Here is a tip that I learned from on of my readers.

If you use the Flirc case for your digital picture frame and glue it to the back of your display, then make sure to turn the Flirc case upside down.

Do it this way, and you can easily take out the SD card or even the board because you have access the screws and don’t need to loosen the case from the display.


The Flirc case is great in so many ways.

Not only does it give your Raspberry Pi a very stylish look but it also keeps your CPU temperature reliable down to a level where no throttling is necessary.

And the aluminum heatsink will not reduce the WiFi signal quality, quite the opposite, it even results in a stronger signal than you would see with no case.

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