A wireless Smart Home combines cutting-edge technologies with simple installation. Thanks to a more affordable price compared to wired systems, it is now truly accessible to everyone. However, since it is a wireless protocol, there are a few important details to keep in mind when building the system. If you neglect them, you may later experience stability issues. In this article, we will look exactly at how to avoid them.
The range problem and a solution you often don't even know about
Technology is moving forward. Today, you no longer have to pull kilometers of cables or install huge switchboards for a smart home. Wireless technologies are at such a high level that using them for a Smart Home is completely natural.
The main challenge with wireless systems is signal range. You probably know this problem from a standard home WiFi network – as soon as you move away from the router, the signal weakens. In Smart Home systems, all devices must reliably communicate with the control unit. If this communication is not stable, devices may not respond to commands or the entire network will slow down.
The miracle called MESH network
To solve dead zones with WiFi, plug-in "extenders" are typically used. However, the most commonly used Smart Home protocols (like Z-Wave and Zigbee) approach this much more intelligently. They use what is called a MESH network.
Imagine a spider web. If you placed 10 points on it, there are many alternative paths between each of them. In a MESH network, not every device has to communicate directly with the central unit. The control unit can be completely at the edge of the house, and yet everything works flawlessly. Why? Because the active elements in the network themselves act as signal extenders and pass it further along.
The red dot is the control unit, the dark blue dots are active elements, the light blue dots are passive elements.
Active versus passive elements
In both Z-Wave and Zigbee networks, we distinguish between two basic types of devices:
- 🔌 Active elements: They have a constant power supply from the mains. This includes lighting control modules (behind wall switches), heating controllers, smart plugs, active relays, etc. All these elements automatically extend the signal.
- 🔋 Passive elements: These are battery-powered. This includes motion sensors, temperature sensors, door contacts, locks, or remote controls. To save battery, they "sleep" most of the time. They do not forward the signal; they only receive and send it.
💡 Important Rule #1: Device distribution
Active elements act as signal extenders. Plan your system so that you have active (mains-powered) elements distributed evenly throughout the house!
The 4-Hop Limit in Z-Wave
There is one limit that is rarely talked about. The signal between thecontrol unit and the end device in a Z-Wave network can make a maximum of 4 hops through other active devices. Since one module in an open space reaches 50-100 meters, with 4 hops we can cover a respectable distance (if the unit is placed in the center of the house, it theoretically covers a huge area). There's no need to worry; for normal houses, this is absolutely sufficient.
*Zigbee does not have a fixed limit on the number of hops, but as the number of hops increases, the system response time (latency) also increases.
Treacherous obstacles and network congestion
What if we have our devices distributed, but the system is still acting up? There are two most common causes:
- Thick walls and aluminum: A wireless signal is not a terminator; it won't break through thick reinforced concrete or aluminum structures. If you have meter-thick stone walls, the trick of bypassing the obstacle will help – just add one smart plug in the hallway and the signal will "bypass" the wall through it.
- Too many sensors, too few active elements: Imagine a system where you have 3 smart plugs but 30 battery sensors. The communication of all these sensors can overload those few points through which the signal passes. A data "traffic jam" will occur.
💡 Important Rule #2: The right ratio
In your system, plan for at least as many active (wired) elements as you intend to have passive (battery-powered) ones.
From point A to point B: The favorite path
Over time, devices in the network create what is known as the last known route. For example, if information from a bedroom sensor always goes first through the smart plug in the living room, the network remembers this shortcut so that communication is lightning fast.
The problem arises when you disrupt this favorite path. This happens most often when a smart plug is unplugged from the wall, or if a classic ripple control (HDO) relay completely cuts the power to a smart thermostat. Suddenly, the path is broken.
If, a few hours later, a sensor on that same route detects motion and wants to turn on the light, it discovers that its usual path doesn't work. The control unit will start polling all surrounding devices to find a new route (so-called network rebuilding). This consumes both system resources and time. You will notice this when you walk into a dark room and the light doesn't turn on, or it turns on several seconds late.
⚠️ Important Rule #3: Do not disrupt favorite paths
Do not unplug active elements from the socket unless you have to. Do not disconnect thermostats from their voltage supply (it's better to connect grid ripple control signals only for information, e.g., via a Fibaro Implant). By physically disconnecting them, you disrupt the harmony of the MESH network and force devices to search for alternative routes, which causes delays.
Multiple protocols in one system
Today, control units (like Homey or Fibaro Home Center 3) that can communicate simultaneously via Z-Wave, Zigbee, WiFi, or 433MHz are very popular. It's great for compatibility. However, beware of an important fact:
A MESH network does not cross over between different protocols!
A Z-Wave plug will not extend the signal for a Zigbee sensor. If you buy a different standard for every room with the vision of saving a few bucks, you might end up with a system that lacks a strong backbone, having instead many isolated islands that barely reach the central hub.
🎯 Important Rule #4: One backbone protocol
Choose one primary protocol that will cover the largest and most important part of your smart home (such as lights and sockets) and allow it to build a strong MESH network. You can connect other "gadgets" later using different protocols, but don't mix up the foundation!
Conclusion: Which protocol for a true Smart Home?
In our portfolio, you will find all technologies represented – from WiFi (such as Shelly), through Zigbee, to Z-Wave. Despite the wide range on offer, after more than a decade of installations, we most gladly return to products on the Z-Wave platform. Here are the reasons why:
- Guaranteed compatibility: While with Zigbee, two products from different brands might not forward the signal for each other, Z-Wave certification strictly requires this.
- Strong and stable MESH network: Z-Wave allows for a stable signal to be drawn across a large house without dropouts. While dozens of cheap WiFi sensors will heavily congest your home network, Z-Wave bypasses your WiFi router and uses its own frequency band.
- Professional products: Z-Wave also offers solutions for switchboards (DIN modules), extremely powerful relays, input modules for integration (Fibaro Implant), or programmable boards (Z-UNO). You won't find these in standard WiFi "toys".
- Excellent availability: While some Zigbee components (e.g., from IKEA) are hard to come by, the Z-Wave portfolio from European manufacturers (like Fibaro, Qubino, etc.) is huge and stably stocked.
Z-Wave devices may not be the cheapest in their initial purchase, and their price might seem higher compared to standard WiFi smart plugs. However, their stability, interoperability, and flawless functionality will quickly return this investment in the form of a peaceful sleep and a truly "smart" home that runs itself.