Every smart home device talks over one of four wireless protocols. Understanding the differences saves you from the two most common mistakes: buying battery devices that die in three months, and buying hardware that physically cannot work in Australia.
Here is what each one is for.
Wi-Fi
Use it for: anything plugged into the wall.
Wi-Fi's advantage is that you already have it. No hub, no bridge, no extra hardware. A Wi-Fi smart plug connects to your router and works.
Its disadvantage is power consumption. Maintaining a Wi-Fi connection draws far too much current for a coin cell. This is why Wi-Fi door sensors and Wi-Fi cameras with batteries have such disappointing runtimes — they survive by sleeping and waking, which introduces exactly the lag that makes a motion sensor useless for lighting automation.
Two practical Wi-Fi issues to know about:
The 2.4 GHz requirement. The overwhelming majority of smart home devices only support 2.4 GHz Wi-Fi, not 5 GHz. If your router broadcasts both bands under a single network name, setup often fails because the phone is on 5 GHz while the device needs 2.4 GHz. The fix is either a temporary split of the bands into separate names, or using a router that handles this gracefully.
Client limits. Smart devices use almost no bandwidth but they do occupy connection slots. Budget routers become unstable somewhere between thirty and fifty clients. A house with lights, plugs, sensors and cameras reaches that faster than people expect.
Zigbee
Use it for: battery sensors, buttons and bulbs, especially if you already own a Zigbee hub.
Zigbee is a low-power mesh network on the 2.4 GHz band. Battery devices last a year or more because the radio wakes briefly and goes back to sleep. Mains-powered Zigbee devices act as repeaters, so the network gets more reliable as you add to it — a genuinely useful property.
It needs a coordinator: a Hue Bridge, a SmartThings hub, an Aqara hub, or a USB Zigbee stick in a Home Assistant setup.
The catch is 2.4 GHz congestion. Zigbee shares the band with Wi-Fi, Bluetooth, microwaves and baby monitors. In an apartment building with a dozen overlapping Wi-Fi networks, Zigbee can become flaky. Choosing non-overlapping channels for Wi-Fi and Zigbee fixes most of it.
Zigbee's other historical weakness was interoperability — manufacturers implemented it loosely and devices from different brands did not always cooperate. This improved a lot, but a device from an obscure brand may still behave oddly on a hub from another.
Aqara Hub M3
Best for: Giving Zigbee sensors and buttons a coordinator to join
What we like
- One of the standard Zigbee coordinators, alongside a Hue Bridge, a SmartThings hub or a USB Zigbee stick in Home Assistant
Worth knowing
- Zigbee shares the 2.4 GHz band with Wi-Fi, Bluetooth and microwaves, so it can get flaky in apartment buildings with many overlapping networks
- Zigbee interoperability is looser than the marketing suggests — a device from an obscure brand may behave oddly on another brand's hub
Philips Hue Bridge
Best for: Running Hue bulbs on Zigbee and exposing them to Apple Home, Google Home and Alexa
What we like
- One of the standard Zigbee coordinators, alongside a SmartThings hub, an Aqara hub or a USB Zigbee stick in Home Assistant
- It is the piece that connects Hue bulbs to Apple, Google and Amazon
Worth knowing
- Zigbee shares the 2.4 GHz band with Wi-Fi, Bluetooth and microwaves, so it can get flaky in apartment buildings with many overlapping networks
- Zigbee interoperability is looser than the marketing suggests — a device from an obscure brand may behave oddly on another brand's hub
Thread
Use it for: new battery-powered devices, particularly if you are building on Matter.
Thread uses the same 802.15.4 radio as Zigbee, so it shares the low-power mesh characteristics. The difference is that Thread is IP-based — every device gets its own IPv6 address and is addressable directly on your network, without a hub translating.
Thread needs a border router to bridge the mesh onto your home network. You may already own one: Apple HomePod mini, Apple TV 4K, Google Nest Hub (2nd gen), several Echo models and the SmartThings hub all provide this.
Thread is the low-power transport for Matter, which means it is where the industry is heading for sensors, locks and buttons. If you are buying new battery devices today and have a border router, Thread is the sensible default.
One caveat: Thread's border router landscape is still messy. Different vendors' border routers do not always form a single unified mesh as cleanly as the marketing implies, though this has improved considerably.
Apple HomePod
Best for: iPhone households that care about sound quality and privacy
What we like
- Best sound quality of the three big assistants by a clear margin
- Strongest privacy position — more processing happens on-device, less data leaves the house
- Acts as a home hub and Thread border router, so automations keep running remotely
- AirPlay 2 groups it with compatible third-party speakers
Worth knowing
- Siri is the weakest assistant for anything beyond home control and timers
- Requires an Apple household — there is no meaningful Android path
- Costs more than the equivalent Echo or Nest
Z-Wave — and the Australian frequency trap
Use it for: situations where 2.4 GHz congestion is the problem, and reliability matters more than price.
Z-Wave operates on sub-GHz frequencies, well away from Wi-Fi. That gives it two real advantages: no contention with your Wi-Fi network, and better range through walls, since lower frequencies penetrate building materials more effectively. Z-Wave's certification programme has also historically been stricter than Zigbee's, so cross-brand compatibility is more dependable.
Here is the part that catches Australians out. Z-Wave's frequency allocation is region-specific, because it uses whatever unlicensed sub-GHz spectrum each regulator permits. Australia and New Zealand sit at approximately 921.42 MHz. North America uses roughly 908.42 MHz. Europe uses 868.42 MHz.
These are not settings. They are different radios. A Z-Wave sensor bought from a US retailer will never talk to an Australian Z-Wave hub, no matter what you do. There is no firmware fix, no region switch, no workaround.
This makes Z-Wave the single riskiest protocol to buy from overseas, and it is a mistake people make regularly — the product page says nothing, the price is attractive, and the device arrives permanently useless.
If you buy Z-Wave in Australia, buy from an Australian retailer, and confirm the listing specifies the ANZ or AU/NZ frequency variant.
The other downside is cost. Z-Wave devices are consistently more expensive than Zigbee equivalents, and the Australian range is narrower than the US one.
Which should you actually use?
For most people building a home today:
- Mains-powered devices — Wi-Fi is fine, and simplest. Plugs, cameras, TVs, appliances.
- Battery-powered devices — Thread if you have a border router, Zigbee if you already have a Zigbee hub. Avoid Wi-Fi sensors unless there is genuinely no alternative.
- Z-Wave — only if you have a specific reason, such as severe 2.4 GHz congestion or a device only available in Z-Wave. Buy locally.
The honest answer is that the protocol matters far less than it used to. With Matter and a decent hub, the underlying radio is largely invisible in daily use. Where it still matters is battery life, reliability under congestion, and whether the thing you ordered from overseas will work at all.
If you want the layer above this, read our explainer on Matter, which is what ties these protocols together.
