We have repeatedly stated on these pages that if you really want to create a complex home automation system with many components, it is not advisable to use a lot of Wi-Fi devices: normal home routers have not been designed to connect dozens of products for the smart home how much to connect phones, smart TVs, computers
There are wireless transmission protocols such as Zigbeee Zwave dedicated to home automation on the market for years that bring a flood of benefits to those who have to set up a smart home and their slow but inexorable evolution brings advantages that standard Wi-Fi can not offer today.
Let's see what they are and how they compare Zigbeee Zwavee especially which to choose or why, in some cases there is no need to choose a priori.
Standard Open and closed
The difference between Zigbee and Z-wave in terms of electronic components that Zigbee independent of the Chip manufacturer and an open standard: in practice you have different chips from different manufacturers that respond to a series of "fairly" standardized protocols. If on the one hand an advantage for the price on the other leads to a fair anarchy for that "enough": it is possible that a device does not respect the general rules of the protocol with the manufacturers who make some changes to better manage the devices with their software.
The best known case is that of Philips with Hue, based on Zigbee: the lamps use the basic wireless protocol but if you want to exploit all its capabilities in a complex system you must have the Hue gateway (bridge element between Zigbee to Wi-Fi) produced by Philips itself which, moreover, directly manages the updating of peripherals / lamps.
The same thing we could say about the Aqara and Xiaomi products use the Zigbee connection protocol that can also be managed directly from other Gateways but with a Hub (gateway or bridge) from the same manufacturer everything works better at first glance.
On the other side Z-wave a closed standard: there is only one chip maker that Silicon Labs and which manages a fairly stable and little modifiable protocol and in theory all products (1,700 at the moment) can talk to each other but not said: the Hub / Gateway manufacturers who also produce sensors try to keep you in their closed park and obviously they tend to better manage compatibility with their production rather than that of third parties by introducing control capabilities that other gateways do not have.
In any case, Z-wave has several advantages including that of having a unique ID that allows the Hub to recognize it without problems and responds to security protocols that have grown over time for quality and reliability. At the moment there are 1700 home automation peripherals and 700 companies that in various capacities use Z-wave for production, installation and integration.
Installation and distribution distances in the home
If there is an advantage that Zigbee and Zwave devices have over Wi-Fi, that of creating a mesh type network. The mesh network is no longer an abstruse concept for the average user: there have been Wi-Fi mesh devices for several months that have made it possible to spread high-speed connectivity throughout the home (see Netgear Orbi, AVM Fritz and other brands) and also Bluetooth in the its latest versions now has mesh capability.
The Wi-Fi network in any case, if you do not use mesh repeaters has a standard "star" configuration and therefore the peripherals farthest from the center that the router will have greater difficulty in communicating and each will do it only with its own strength.
On the contrary, in a mesh network, each element acts as a bridge for the passage of data to the other element and to the gateway that acts as a sorting center.
Zigbee and Z-wave were born from the beginning with mesh capability for a simple reason: creating an interchange network between different devices that are always powered increases the redundancy of the connections and being able to manage the nodes in this way allows you to sensitize every corner of the house in a configuration that no longer star-shaped but with intertwined links in which each device acts as a bridge for the neighboring one, creating a series of chains that intertwine according to the topology of the room and peripherals.
In this type of basic configuration, the distance between the individual nodes and the wireless transmission capacity which also depends on the frequency used.
Since Zigbee is based on 2.4 GHz and Z-wave travels around (we will explain this "around" later) at 900 MHz it is clear that the former will have less diffusion capacity within the domestic walls and, to create an efficient network we will have to have meshes of shorter length where the individual devices are at a shorter distance from each other.
Typically (and simplifying a lot) the distance covered by Zigbee is around 10-15 meters while that covered by Z-wave reaches 30 meters but all this depends on the type of walls that are in the middle. Typically you will need to have a Zigbee node with power in each room while with Z-wave you may need two or 3 knots per floor.
In general, this type of problem does not occur in a house with a widespread home automation system but if your installation is very basic, with very few devices discreetly distant from each other then you could rethink the use of Wi-Fi (provided that this has good coverage throughout the house – maybe with a Wi-Fi mesh repeater).
Difference between Mesh nets
Even if Zigbee and Zwave are based on the principle of the mesh they do not behave exactly the same way in data transmission: if the purpose of the mesh to reach the central gateway the signal jumps (hop) from one node to another and if Zigbee can potentially performing an infinite number of jumps, Z-wave can only perform 4 jumps and in practice if the 3 closest devices compatible with the jump are far from the Hub, the chain is interrupted: even if this is compensated by the greater range seen in the chapter previous need to take this into account when designing a home network on very large apartments.
Disturbances on the network
Z-wave operating on a frequency free from traditional Wi-Fi your and your neighbors and other devices less prone to interference that can damage the mesh network spread throughout the house. In this Z-wave certainly less subject to disturbances on the network.
Energy and battery
If as we said Zigbee and Z-wave have huge advantages over Wi-Fi over consumption (especially in standby if you consider that a lamp, an outlet or a switch with Wi-Fi consumes even more than double in the rest / standby phase of a Hue lamp – 0.45 W) and there are differences between the two protocols with an advantage in favor of Zigbee that is less greedy for energy and therefore favored in the use of the installation of sensors since the battery change will occur less frequently: this reduces also the maintenance and management times of a complex plant.
Plus Zigbee devices, thanks to a collaboration with Enocean they can also use l Energy Harvesting (which we have explained on this page) which in fact avoids the user to insert a battery and having to manage its change: we are comfortable in devices that can collect light, temperature difference and mechanical energy such as the Vimar switches that we have tried on this page .
In any case, as we have repeatedly affirmed, installing always powered devices (lamps and relays / switches) with Zigbee and Z-wave (and also Bluetooth) represents an excellent saving of the home automation system at rest or in standby compared to traditional Wi-Fi peripherals.
International products – beware of Z-wave!
While the 2.4 GHz operating frequency of Zigbee is the same all over the world that of Z-wave different from continent to continent to adapt to national radio wave legislation and therefore a Z-wave peripheral purchased in the USA or Australia works with a frequency different from that used in Europe as it is incompatible or not installable.
Here is the list of the main Z-wave frequencies worldwide expressed in MHz
- Europe and French Guiana: 868.40, 868.42, 869.85
- China, Singapore, South Africa: 868.4
- Australia, New Zealand, Malaysia: 921.4; 919.8
- Hong Kong: 919.8
- India: 865.2
- Russia: 869
- USA, Canada, Argentina, Guatemala, The Bahamas, Jamaica, Barbados, Mexico, Bermuda, Nicaragua, Bolivia, Panama, British Virgin Islands, Suriname, Cayman Islands, Trinidad & Tobago, Colombia, Turks & Caicos, Ecuador, Uruguay: 908.4; 908.42; 916
- Israel: 916
- Japan and Taiwan: 922 – 926
So pay attention to both purchases and any transfers of your systems to other homes abroad: your Z-wave peripherals may not work in the new home.
What can we recommend for a wireless home automation system?
Given the current production and given the premises, the best advice is to choose based on two or three parameters: the size of the house, the number of sensors and devices to be installed, the type of home automation tools you want to use.Obviously they are very general advice and for medium complex systems an adequate preparatory study must be done … but take them as basic advice ….
Small house, few peripherals
If you need to install very few switches or just a kit for roller shutters and / or garage and you have something with excellent wireless coverage you could rely on Wi-Fi and pair a Philips Hue Zigbee Wi-Fi gateway for the lamps, or, if not you have problems with privacy an Amazon Echo Hub (maybe Plus or Show that have Zigbee on board for other peripherals). The same applies to those with Homekit: Wi-Fi sockets and slippers, Hue Philips with Zigbee and an Apple TV to manage bluetooth even in your absence are sufficient.
Medium or large house, few or many peripherals
If the house you need to house large enough (say above 60-70 meters) and / or on two floors start thinking about a network with Zigbee or Z-wave by installing a Zigbee peripheral powered in each room or a Z-wave powered every 2-3 rooms, always combine a Philips Hueo Tadfri lighting system from Ikea or Zigbee with Amazon Echo (if you like voice control) or third party.
If the really big house you resort and you have many peripherals resort to a cross-platform hub or gateway that has both Z-wave and Zigbee (and maybe also Bluetooth, Radio Frequency and IR): there are not many on the market: we have tried two as valid as Samsung Smartthings marketed by Vodafone and Homey which is also compatible with Homekit.
Plant level integration with the new civil series
We should also remember that some civil series with home automation integration have been on the market for a few months such as Bticino – Legrand – Netatmo's Living Now which has its own gateway that connects Wi-Fi and Zigbee and can be integrated with Alexa, Google and Homekit. It can be a starting point or an enrichment of the system being renovated: remember the characteristics of zigbee in case you want to design a system for your home.
The combination of a series of this kind with a cross-platform hub or gateway enables you to practically support any device on the market and to control any aspect of your smart home.
Note: this article is open to your requests for advice and suggestions and will be integrated with links and insights.