How Does Z-Wave Actually Work?

If you’ve made even the first tentative steps into home automation, chances are you’ll have come across Z-Wave and maybe you’ve wondered what it’s all about.

Today, we’ll examine how Z-Wave actually works but, before that, it’s necessary to look at the basics starting with what does it even mean?

The Basics: What is Z-Wave?

Z-Wave is a remarkably efficient and wireless technology for home automation.

Conceived by Zensys Inc, a Danish start-up in 2001 as a cost-effective alternative to Zigbee, and launched in 2004, the express intention was to offer dependable communication between devices from different manufacturers. The Californian firm Sigma Designs acquired the company in 2009. Silicon Labs recently bought out the business for $240 million.

Operating on minimal power, you’ll get no interference with your WiFi signal. Unlike the 2.4GHz band used by your home WiFi network or competing protocol Zigbee, the 900MHz band used by Z-Wave not only slashes interference at this lower frequency but also offers a longer wavelength more capable of penetrating obstacles like walls and ceilings.

So…

The Z-Wave protocol makes use of low-energy radio waves to enable communication between smart devices and appliances in your connected home.

In order to see how Z-Wave works, it’s crucial to understand a little about mesh networks. When you’re clear on the general principles of mesh network topology, you’ll see more easily how Z-Wave, specifically, works.

What Is a Mesh Network?

If you think about a regular RF network, the more devices you add, the more it slows down, and the more interference you experience.

Mesh networks operate differently to avoid these problems.

The more devices you add to a mesh network, the stronger it becomes. When a new device is added, it weaves itself into the mesh and the best pathways for data transmission are created with each device acting as a repeater. The exception to this is battery-powered devices. It’s only those plugged into an outlet capable of performing as repeaters.

With a regular WiFi network, all devices connect to a central hub, usually a router. With a mesh network, while the devices normally link to a hub, they also link together to form a mesh. The devices are not WiFi-enabled and simply use Z-Wave connectivity to communicate with the hub. Since signals are able to hop from device to device, this communication does not need to be direct giving you further versatility.

A mesh network is comprised of nodes which, for the purposes of home automation, are smart devices. You can have up to 232 nodes, the one area where Z-Wave loses out to its arch rival Zigbee which allows for 65,000. That said, this is still more than enough for even larger smart homes.

We looked here at the differences between these two leading protocols if you’d like a head-to-head comparison. Next week, we’ll also be pitting Z-Wave against Insteon so you can fully assess your various options.

Note: You don’t necessarily need to choose between these protocols and remain completely locked into just one. Both the Wink Hub and Samsung’s SmartThings Hub offer Z-Wave and Zigbee support. Plenty of other devices from Yale and Honey through to a suite of GE appliances all work equally well with either protocol.

With mesh networks, messages can be successfully relayed between a pair of nodes even if they are not within range of each other. If there’s a third node that can communicate with both of the other two, the message can still be reliably passed on. When optimal paths are not immediately found, other routes are attempted until the message hops on.

The advantage of this system is that a Z-Wave network gives you much wider-reaching coverage than you’d get from the radio range a single unit delivers.

On the flipside, there’s sometimes a very slight delay between the control command and outcome.

Z-Wave: Layer upon Layer

Z-Wave systems have 3 separate layers:

  • Radio
  • Network
  • Application

It’s the way in which these layers all work together that creates such a seamless, dependable network.

For the purposes of how Z-Wave actually works – and we’ll be getting to that soon once the groundwork is laid and all terminology explained – it’s the application layer that counts. It’s based on this layer that devices are able to communicate with each other.

Before anything else, a few more terms that will help you more thoroughly grasp the principles of a Z-Wave system.

Some More Z-Wave Terminology

The full spectrum of Z-Wave devices can be neatly grouped into 3 main categories:

  • Controllers: Used purely to control other Z-Wave devices
  • Sensors: Reporting devices that send data using analogue or digital signals
  • Actuators: Controlled devices that switch signals

Controllers

Controllers come in many guises.

Some Z-Wave remote controls are simply universal remotes equipped with IR.

You can also buy proprietary Z-Wave remote controls. These have dedicated keys to streamline grouping, scene selection, and general network functions.

You can also access Z-Wave networks on a PC via USB sticks or IP gateways. If you use a gateway, you can also remotely access your network online, something not possible with a physical controller for obvious reasons.

Many Z-Wave devices can also be controlled in-app using your smart phone.

Sensors

Analogue sensors are used for measuring temperature and humidity. They also work well for determining gas concentration in the case of carbon monoxide detectors, for instance.

Digital sensors come into their own for motion detection, water leak warning, and any doors or glass breaking.

Actuators

Actuators use analogue signals for electrical dimmers and controlling motorized blinds.

For electrical switches and electrical displays, an actuator uses digital signals.

With motor control and thermostat control, either type of signal can be used.

OK…

Now to the easy part and how Z-Wave actually works.

How Does Z-Wave Actually Work?

Z-Wave works as a wireless and secure mesh network.

You control your devices as outlined above by controller, key fob, smart phone, tablet or computer.

A command is sent from whatever controller you’re using to a hub and then this command is routed to the destination device. The hub is essential if you want remote access.

Communication takes place using the 2-way system baked into Z-Waves devices so everything happens in the background without any user input beyond making the command.

Devices need to be added into the network – included – before they can be controlled.

The network itself has a Network ID while the devices are classified with a Node ID. The separate network ID ensures there will be no clash or security risk if your neighbor also uses a Z-Wave system in their smart home.

We’ll strip down the science now of how communication takes place beneath the hood.

Command Classes

Command classes are simply groups of responses and commands linked to the ways in which devices function.

An example: a standard on/off switch is known as a binary switch. This has 3 different commands (SET, GET, REPORT) so the command is sent to the switch then back to the controller for the purposes of reporting. The command class binary switch allows a device to deal with all these elements.

Different devices use different command classes. There is a Basic command class supported by all devices that facilitates communication between devices even if they’re not sure of the specific functions of the other devices.

Device Classes

Beyond the Basic command class, device classes are used so that devices from different manufacturers are able to work in harmony.

Device classes work on 3 levels:

  • Basic Device Class: Devices are termed either controllers, slaves or routing slaves
  • Generic Device Class: This device class relates to basic functionality the devices will support in the capacity of either controller or slave. Examples include static and generic controllers, binary and multi-level switches, sensors, meters, and thermostats
  • Specific Device Class: Specific device classes break down the generic classes further, for example, a multi-level power switch or a setback thermostat

There are further optional command classes beyond the mandatory classes above.

The device announces these classes during inclusion along with all optional classes. This process ensures all devices are fully optimized.

So, that’s what’s happening underneath everything in your Z-Wave network in plain English.

The Benefits of Z-Wave

We’ll highlight some of the key benefits of Z-Wave so you can see at a glance where this protocol wins out… 

  • Affordability: You can get going with a Z-Wave system without needing to throw too much money at it. Adding products over time is straightforward so there’s no crushing initial investment required
  • Ease of Installation: You won’t need to mess about with rewiring and, although some degree of technical knowledge is required, set-up really is a breeze
  • Interoperability: Most of the major smart home players offer Z-Wave support. There are an estimated 2400 devices to choose from and, with over 90 million Z-Wave products already nestled in smart homes worldwide, it’s a protocol with compatibility uppermost and rock-solid
  • Reliability: You’ll get reliability in two ways. Firstly, Z-Wave is well established and has been in operation for 15 years now. Beyond this, the mesh network system gives you an extremely dependable communication protocol with very little interference for the double-win            
  • Security: Robust encryption and security is AES-128 as used by banks and government organizations

The only drawbacks worth mentioning are the limited number of nodes, but, as we mentioned, support for 232 devices is more than fit for purpose.

It also helps to have at least some knowledge of radio frequency but that’s why we’ve brought this study to you today!

So, how about the Z-Wave Alliance?

This is another one of those terms you might have encountered without really investigating it further but the concept is pretty simple.

The Z-Wave Alliance

With over 700 members manufacturing 2400 products, the Z-Wave Alliance was established in 2005.

The Z-Wave Alliance is responsible for certification and makes sure that every Z-Wave device conforms to rigid standards. The result of the Z-Wave Alliance is that every Z-Wave controller will assuredly work with every Z-Wave device. This complete interoperability is where Zigbee sometimes falls down.

All you need to look out for when you’re shopping is the Z-Wave Certified sticker, and you’re in safe hands.

How Do Z-Wave and Z-Wave Plus Differ?

In a sense, Z-Wave Plus is old news even though it’s still used for marketing purposes.

The platform underwent a substantial upgrade a few years back with range and battery life boosted, and extra channels added.

The vast bulk of Z-Wave products currently on the market will be Z-Wave Plus, also known as the Z-Wave 500 series.

OK…

Now you’ve got a decent grounding in how Z-Wave actually works, what do you need to get started?

Luckily, nothing but a few simple devices and a controller will get you up and running without costing you a fortune.

6 of The Best Z-Wave Smart Home Products

While you’re spoiled for choice with Z-Wave gear, we’ll round out with just a half-dozen options to get you started in fine style.

Hub

Wink Hub 2

If you’re looking to build out a comprehensive connected home and you’re not quite sure about protocols, starting with Wink’s legendary hub eliminates the need to compromise…

Compatible with Z-Wave and Zigbee, Bluetooth LE and Lutron Clear Connect, you can set the foundation for pretty much any smart devices you want to add over time.

You’ll also be spoiled with connectivity. Choose between the non-congested 5GHz WiFi band or use the Ethernet port for an even more solid connection.

Now into a slimmer second generation, you’ll enjoy enhanced local control, uprated memory from 64 MB to 512 MB along with auto-discovery and guided set-up. This renders installation a cinch even if you’re not the biggest tech-head.

You can pair up to 530 devices from a selection of over 400 viable options from all the main smart home brands. Control is super-simple in the slick, intuitive Wink app.

While Samsung’s mighty SmartThings Hub is also Z-Wave compatible, for versatility married to potent performance, Wink Hub 2 gets our vote as best overall gateway for your Z-Wave devices and much, much more.

Controller

Universal Devices PRO Controller

Universal Devices serve up a wonderful controller that works equally well with Z-Wave and Insteon devices and allows you to take direct charge of your devices and appliances. This is absolutely not a device for everyone. The thing is, if you’re going the Z-Wave route, that presupposes a degree of technical know-how. That being the case, we appreciate you might want robust control and the PRO delivers fully.

This controller is not a cloud-based variant so you’ll get unparalleled reliability with no connectivity issues at all. Physical control takes place from an IR remote. As part of a Z-Wave system, this controller also serves as a repeater.

Agave app allows you to automate your Z-Wave devices with any compatible Z-Wave ISY controller. From locks and thermostats to dimmer switches, you can take charge of your new Z-Wave kit with a great deal of flexibility.

To reiterate, this is not a controller for beginners, but if you’re looking to take your Z-Wave kit to the next level, you can take full advantage of this feature-rich and field-upgradeable controller at a very keen price point.

On/Off Switch

GE Z-Wave Plus Wireless On/Off Smart Switch

For full wireless control of a hard-wired light source, as long as you have a certified Z-Wave gateway in place, this GE on/off switch is a must.

As with all uprated Z-Wave Plus products, the processor and memory are dramatically improved while you can control devices from an impressive range of 150 feet.

This GE works equally well with multi-switch or single-switch applications giving you total flexibility. You’ll be able to automate your lighting or fans and schedule them to suit and this switch works with just about any kind of light bulb. It also works with fans and pumps or other small appliances.

For voice control, you can use Alexa assuming you have an enabled device so you’ll get great scope for smartening up your appliances without needing to take out a bank loan.

Installation is simple using your existing wiring so dip your toes into on/off switches with this Z-Wave certified beauty from the stellar GE.

Dimmer Switch

Cooper Wiring Aspire RF Smart Dimmer with LEDs

While we could easily have recommended another GE switch for dimming purposes, the Aspire from Cooper Wiring makes a solid substitute.

All you need to do is replace your regular switch with this smart alternative and you can embrace both local and remote control with the ability to turn your lights on and off or dim them to set the mood for your evening without needing to jump out your seat.

If you don’t want the hassle of traveler wires or 3-way wiring, you can create virtual 3-way remote control so you can take charge of multiple locations.

You can choose to employ an Aspire RF controller or any other Z-Wave certified controller and you won’t need any new wiring with the dimmer slotting into a regular wallbox.

The array of 7 LEDs lets you see the brightness level at a glance from the switch itself, a nice touch and something that adds to the already sleek aesthetic.

The default dimming delay is 4 seconds, but you can build this fading out to as much as 4 minutes, perfect when you’re grabbing your things and readying to head upstairs and you don’t want abrupt darkness before you’re quite ready.

Smart Lock

August Smart Lock Pro

The upscale August Smart Lock Pro is a superb entry point if you’re just testing the Z-Wave waters.

One of the key selling points of the August range is their proprietary DoorSense. If you’re not confident about leaving technology to lock your doors for you, this nifty feature allows you to check in and confirm that everything is tightly secured.

Since this model attaches straight over pretty much any deadbolt already in place, you’ll even be able to use your existing keys.

Looking lean and mean in either silver or dark gray, you control your entry system in-app. If you invest in the Connect Bridge, your doors will even automatically lock as you leave.

If you have lots of contractors or staff in and out of your home, you can kiss goodbye to mayhem sharing keys and worry about security being compromised by setting timed access codes. This lock also works well if you rent your property out on Airbnb, streamlining access for customers and making your life even easier.

You’ll be able to use Alexa, Siri, or Google Assistant to take charge of your lock using voice commands and connectivity is equally diverse. Along with Bluetooth, WiFi and HomeKit, Smart Lock Pro is also Z-Wave Plus compatible to complete an impressive line-up.

Sensors

Dome Door and Window Sensors

To round out of look at the best Z-Wave products for your smart home, these Dome sensors are a cost-effective way to add a layer of security to vulnerable doors and windows.

Assuming ideal conditions and minimal obstructions, range extends to a full 150 feet as with all the newer Z-Wave Plus devices.

Whether you want to keep your eye on doors or windows, cabinets or garage doors, this compact and battery-powered sensor is plug-and-play in its simplicity yet delivers extremely powerful performance. The single battery gives you 3 years of lifespan and you get a broad operating temperature from 32 through 104 degrees Fahrenheit.

For a superb Z-Wave sensor at a price you’ll love, we can’t recommend the Dome strongly enough.

Final Word

We hope today’s detailed look at how Z-Wave works has given you a much more precise idea of how you can harness this dependable communication protocol in your connected home.

Next up on our home automation blog, we’ll be pitting Z-Wave against Insteon so you can see where these two giants stand and fall. Come back soon for more of the latest smart home news and all the best products broken down for you.

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Reference: Smart Home