The Raspberry Pi is most likely the top device for newcomers as well as experienced users to run Home Assistant on. It’s small, cheap, quiet, and doesn’t use much electricity. A Raspberry Pi was my gateway drug into home automation and self-hosted software, and I have since moved on to a “proper” server. The Raspberry Pi is still what I would recommend if you just want to get your toes wet, and this article will list the best Raspberry Pis for Home Assistant you can buy.
Home Assistant currently recommends you run the software on either a Raspberry Pi 3 Model B, a Raspberry Pi 3 Model B+, or Raspberry Pi 4 Model B. In my opinion, you should only be considering one of the three recommended models. Let me explain.
Raspberry Pi 3 vs. Raspberry Pi 4 for Home Assistant
As recommended by the developers of Home Assistant, it is ill-advised that you attempt to run it on anything older than the Raspberry Pi 3 Model B. This includes the original Raspberry Pi and the Raspberry Pi 2. And while the Raspberry Pi Zero might be a popular platform for applications such as Pi-hole and room-assistant, it just isn’t powerful enough to handle Home Assistant.
With that in mind, you might be debating whether to go with a Raspberry Pi 3 Model B/B+ or Raspberry Pi 4 Model B for Home Assistant. While you might be able to buy either Raspberry Pi 3 for less money, there are some serious drawbacks, which I’ll discuss next.
The Raspberry Pi 3 networking bottleneck
While the Raspberry Pi 3 Model B and Model B+ do feature a gigabit wired LAN (GbE) adapter onboard, they are hampered by the USB 2.0 bus speed. I won’t get too technical here, but there are some serious drawbacks to this.
You should be expecting ~950 Mbps (megabits per second) from a true gigabit connection. But because of the Raspberry Pi 3’s networking bottleneck, you will be limited to around ~225 Mbps instead. Such a drop in speed will be very noticeable.
Faster USB speeds on the Raspberry Pi 4 Model B
The Raspberry Pi 4 Model B not only boasts true gigabit Ethernet, but also faster USB ports. As usual, there are four in total, but two of them get an upgrade to USB 3.0. This is more important than it might seem.
Once you start working with a Raspberry Pi, you will likely make the unfortunate discovery that microSD cards aren’t very reliable. That is, of course, if you don’t follow my guide on how to purchase the best microSD card for your Raspberry Pi running Home Assistant. In general, microSD cards are known to corrupt, especially when data is written to them frequently. This has led many in the community to move their installation onto an SSD connected via USB. A USB 2.0 port would in this case again be an unnecessary bottleneck.
Faster CPU, better GPU, and more RAM
While the Raspberry Pi 3 Model B+ only showed marginal gains in performance when put up against the Raspberry Pi 3 Model B, the Raspberry Pi 4 Model B is a big improvement. The MagPi magazine published some impressive benchmarks shortly after the Raspberry Pi 4 Model B was released.
The Raspberry Pi 4 Model B features an upgraded CPU and GPU. The CPU has a slightly higher clock speed and has a newer, more efficient architecture than that found in the Raspberry Pi 3 Model B/B+. While it might not look like much on paper, in the real world there is a noticeable difference. The same goes for the GPU, which should be capable of playing back 4K/60FPS H.265-encoded video.
The basic Raspberry Pi 4 Model B, which is being sold for the same price as the Raspberry Pi 3 Model B/B+ were on introduction, boasts four times the amount of RAM over what is available on its predecessor. With the Raspberry Pi 4 Model B, there are also models with 4 GB and even 8 GB. Considering many smartphones ship with over 8 GB of RAM, this might not seem like much, but it is more than enough to run a lightweight Linux distribution, such as the Home Assistant Operating System.
How much RAM does Home Assistant need?
So, you have decided to go with the Raspberry Pi 4 Model B for Home Assistant. Good choice! But, as mentioned earlier, there are different versions available. The Raspberry Pi 4 Model B comes with either 2 GB, 4 GB, or 8 GB of RAM (it appears that the 1 GB model is no longer produced, but you might find still find it for sale).
A Linux engineer would probably tell you that you can never have too much RAM and thus should go with the 8 GB. But let me tell you that Home Assistant doesn’t need a lot of RAM. In fact, you will probably get by with just the 2 GB. And at just ~$35 that configuration is a bargain. But if you are planning on using any of the many plugins and want to use the Pi for more than just a gateway drug, I recommend that you go with at least the 4 GB Raspberry Pi 4 Model B. At ~$55 you still get a lot for your money.
Don’t forget the extras
Be warned, that if you buy just the Raspberry Pi 4 Model B, that is all you will be getting. You will need a powerful enough power supply (I suggest going with the official one) and potentially a case. I also recommend the use of a wired network connection and not relying on Wi-Fi, so make sure you have a spare Ethernet cable lying around. There are also kits available which include everything you need.
The Argon ONE M.2 is a popular and highly rated case for the Raspberry Pi 4 Model B. The case itself acts as a massive heat sink, and it has a fan for active cooling. And that isn’t even the best thing about the Argon ONE M.2. As the name suggest, there is space for an M.2 SATA SSD in the bottom half. Even if you start off with a microSD card, this case will future-proof your Raspberry Pi 4 Model B setup.