What is Thread, and why does it matter in a smart home?

Thread is a label you’ve probably seen increasingly often if you’ve been shopping for smart home accessories in the past couple of years. It’s entirely possible, though, to have missed what Thread is, or why you should care — in which case here’s a primer on the technology, why you should be hunting it down, and some of the best Thread devices you can buy.

What is Thread?

At its core, Thread is a wireless protocol based on Zigbee, a low-power standard already used by a number of smart home accessories. It’s not uncommon to see products like smart bulbs and motion sensors support Zigbee, precisely because they can operate with minimal power consumption — even a Bluetooth sensor needs to be larger than a Thread or Zigbee equivalent for the sake of a bigger battery. Wi-Fi, meanwhile, is so energy-hungry that most smart home products with it can only be plugged in.

Being separate from Wi-Fi, Zigbee and Thread also reduce the burden on your Wi-Fi router. A prime of example of this is the Philips Hue ecosystem, which connects up to 50 Zigbee lights to a single Wi-Fi hub. If you were to use 50 bulbs with individual Wi-Fi connections, even a Wi-Fi 6E router would probably become oversaturated.

Another shared feature is that the protocols create “self-healing” meshes. That is, accessories can talk directly to each other without a hub or the internet, and if one is problematic, the mesh can re-route traffic. A light bulb on the opposite side of your house can still communicate with hardware closer to you so long as there are enough devices with Thread or Zigbee in between to form a relay.

The major split is that unlike Zigbee, Thread devices can talk to the internet and each other via native IPv6, regardless of their manufacturer — that’s IP as in Internet Protocol, the numerical address format used by most things online. The only real requirement for Thread products reaching the internet and/or establishing a local network is a “border router,” and many Thread accessories are able to operate as their own. Zigbee devices invariably need a hub.

Why is Thread a big deal?

The need for dedicated hubs has limited the potential of Zigbee, as well as a similar standard, Z-Wave. People can be reluctant to spend the extra cash on a hub, or may not have the know-how to install one and pair accessories. In some cases you need brand-specific hubs to get accessories to work with their full feature sets. You can pair Hue lights with third-party Zigbee hubs, for instance, but you shouldn’t expect to get the same level of control.

The situation has led to many accessory makers sticking with separate Wi-Fi connections and all the limitations that follow. On top of the aforementioned power issues, depending on Wi-Fi means that every device has to connect straight to a central point, i.e. your router. If that point is oversaturated or too far away, you’ll run into dropouts.

Many Wi-Fi accessories further depend on cloud services for automations. If there’s an internet outage, those automations simply won’t run. That can be a serious problem if you’re counting on them to keep you safe and comfortable.

Thread not only deals with these problems, but reacts faster. Whereas Wi-Fi accessories can sometimes take a few seconds to respond to commands, Thread is nearly instantaneous. It’s even faster than Zigbee or Bluetooth, eliminating awkward delays, especially for things like motion-triggered automations.

We have yet to address Thread’s biggest selling point, however — its association with Matter.

Why the hype for Matter over Thread?

You can read more in our Matter guide, but the short synopsis is that Matter is a networking protocol that allows smart home accessories to work with all major platforms, including Amazon Alexa, Apple HomeKit, Google Home, and Samsung SmartThings. To date, the industry has been fractured by compatibility problems — newcomers may have no idea which products will work with what, and/or find themselves unable to use their platform of choice. Matter should solve all of this once more products are updated for it, initially excluding some categories like security cameras and robot vacuums.

On a technical level, Matter supports mesh networks not just over Thread but also Wi-Fi and Ethernet. This means less reliance on hubs overall, or even the internet. You’ll still need a Matter-compatible “controller” device for things like remote access, but while you’re at home, even your phone should be sufficient for control and updates.

Thread is Matter’s ideal infrastructure, being designed with smart home meshes in mind, and improving the speed and reliability of accessories across multiple platforms. In fact the more Thread products you own, the more resilient your mesh becomes. Expect Matter over Thread to become the default for many accessories in the future.

Are there any drawbacks to Thread?

The technology’s biggest limitation is bandwidth. It carries much less data than Wi-Fi, so it simply can’t handle things like streaming audio and video. Though some smart speakers, displays, and TV add-on streamers include Thread, that’s just for linking other accessories, not streaming media or checking your doorbell camera. Thread is better suited to things like lights, sensors, locks, plugs, thermostats, and small appliances like air purifiers.

Because it’s mesh-based, you’ll also want Thread products strewn throughout your home to see the full benefits. It’s pointless to have a Thread-based light bulb, say, if it’s too distant from a border router most of the time. You probably don’t need Thread in every room, but the more devices the better, and you should have at least one border router, preferably contained in the same device that acts as your Matter controller. Some examples include Amazon’s 4th gen Echo and Google’s 2nd gen Nest Hub.

Some confusion is still being sorted out. It’s not always clear which accessories operate only as endpoints rather than as border routers, and because Matter is relatively new, some implementations of Thread remain platform-specific. You can’t count on a HomeKit Thread device linking with Alexa unless the Matter label is there.

Once Matter is commonplace and there are enough Thread products in homes, however, most of these things should become non-issues. Thread is the future, so whenever there’s a choice, pick the Thread-capable product.

The best Thread-ready devices

Eero 6 Plus

While the Eero 6 Plus is first and foremost a Wi-Fi 6 mesh router, each unit doubles as a Thread border router. If you need to upgrade your Wi-Fi, that makes it an easy way of scattering Thread throughout your home at the same time.

For Wi-Fi the 6 Plus is extremely easy to set up and manage, especially if you have Alexa. It can also handle gigabit internet, and unlike some mesh routers, each unit has its own Ethernet ports. The sweetest part is that you can get a three-pack for $299 or less, enough to cover homes up to 4,500 square feet (418 square meters).

Eve Motion

The Eve Motion detects both motion and (with the Eve app for iOS) light levels, so you can use it to trigger automations based on real-world lighting conditions. You might, for example, set room lights to be activated by motion only if it’s dark enough, whether because of clouds or approaching night. It’s also IPX3 water-resistant, so you can use it outdoors or in your bathroom, unlike a lot of the competition.

We’ve linked a Matter-compatible model below, which requires both a Matter controller and a separate Thread border router. Be careful, because there’s another version limited to control with the Eve app or HomeKit, even then requiring an Apple TV 4K or HomePod as a hub.

Nanoleaf Essentials Matter Light Bulb

On their own, Nanoleaf Essentials bulbs are merely alright — you can get better bulbs from Philips Hue — but they’re affordable and some of the first to support Matter over Thread. Without Matter or Thread, they’ll still work over Bluetooth using the Nanoleaf app.

Like the Eve Motion, you’ll need a Matter controller and a Thread border router. If you’re a Nanoleaf fan, the company’s Lines, Shapes, and Elements panels can act as border routers if you have the 8.5.1 update or later.

Apple TV 4K

We’ve tried to avoid being too Apple-centric in this list for obvious reasons, but as you may have gathered, it’s difficult. Apple was one of the earliest Thread adopters, so HomeKit has long had Thread baked in. 

The Wi-Fi Plus Ethernet version of the Apple TV 4K operates as both a Thread border router and a HomeKit hub, which can make it vital in any HomeKit setup. That’s also true of the latest HomePods, including Minis, but the Apple TV 4K is arguably the best media streamer you can buy even if you don’t care about HomeKit. It offers excellent performance, a simple interface, and virtually any app you could want, including many games.

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