I stumbled into this particular topic because of a real-world frustration. Back when I lived in a one-bedroom, one-bath condo, I had an automation that would shut off all my lights and media devices when I left the house. With a relatively small Z-Wave and Zigbee network, this worked great—everything turned off almost instantly.

However, when I moved into a three-bedroom, three-bathroom townhouse and kept expanding my smart home setup, I noticed something strange: when I ran the same automation, I found myself waiting over 30 seconds for all my lights to turn off. What had once been seamless had now become frustratingly sluggish.

That’s when I started digging into how Z-Wave and Zigbee handle device communication, specifically unicast vs. multicast messaging. Along the way, I learned how different Z-Wave generations impact performance and why Zigbee’s built-in group multicast makes a massive difference for large-scale automations.

One of the biggest bottlenecks I discovered was my HUSBZB-1 Z-Wave/Zigbee USB stick, and this led me to a deeper realization about Z-Wave generations and network performance. This stick uses a Z-Wave 500 chipset, which does not support multicast messaging. That meant every time I triggered my automation, the hub was sending out individual unicast messages to every device in my home, instead of efficiently broadcasting a single multicast command. This realization was a turning point—I needed to rethink my setup if I wanted to bring my automations back to the level of responsiveness I expected. Realizing that my controller itself was a bottleneck led me to dig deeper into Z-Wave generations and how older devices can impact network performance.

This whole journey is exactly why I created this platform Bits & Bolts—a platform where I share technical bits of information that I find useful and short insights that make a difference in real-world applications. The "Bits" represent the technical knowledge and small optimizations that can completely change how you approach home automation. The "Bolts" are a nod to hands-on DIY projects, like building and optimizing smart home networks. Whether it's tweaking automations, improving device communication, or integrating new technologies, Bits & Bolts is about combining knowledge with practical execution.

Unicast vs. Multicast: How Zigbee and Z-Wave Handle Communication

One of the key concepts in home automation is how devices communicate. Whether you're turning off a single light or shutting down an entire room, the difference between unicast (one-to-one) and multicast (one-to-many) communication can make a big impact on performance. Zigbee and Z-Wave handle these differently, which affects how quickly and efficiently your smart home responds.

Unicast Communication: One Device at a Time

Unicast is the most common way smart home devices communicate.

Definition: A direct, one-to-one message between two devices.

Used By: Both Z-Wave & Zigbee for individual device control.

Pros:

• Reliable message delivery.
• Ensures each device gets a dedicated response from the target.

Cons:

• Can be slow when controlling multiple devices at once. For example, turning off 10 lights individually creates noticeable delays.

Multicast Communication: Instant Group Control

Multicast is where Zigbee really shines, allowing devices to respond simultaneously.

Definition: A single command is sent to multiple devices at the same time.

Why Zigbee Wins:

• Zigbee natively supports multicast groups, meaning you can send a command to an entire group of devices instantly.
• This allows for near-instant control, like shutting off every light in a room in perfect unison.

Z-Wave’s Limitation:

• While Z-Wave technically supports multicast, most hubs don’t fully implement it.
• Instead of sending one command to all devices, it often resorts to sending multiple unicast messages, causing delays.
• Z-Wave associations can enable multicast-like behavior, but many devices limit associations to only 5 nodes per group, making large-scale automation more difficult.
• While Z-Wave technically supports multicast, most hubs don’t fully implement it.
• Instead of sending one command to all devices, it often resorts to sending multiple unicast messages, causing delays.

This difference is one of the main reasons I prefer managing a Zigbee network over Z-Wave—multicast makes bulk control seamless.

Zigbee 1.2 vs. Zigbee 3.0: Why It Matters

Just like Z-Wave, Zigbee has evolved over the years, improving security, device compatibility, and efficiency. Understanding the differences between Zigbee versions helps in building a more reliable and future-proof network.

Zigbee 1.2

Released: ~2006
Max Range: ~10-20 meters (30-60 ft) indoor range
Security: Basic encryption, weaker than later versions
Routing Efficiency: Standard mesh
Best For: Older Zigbee devices, but less reliable in mixed networks.

Zigbee 3.0

Released: ~2016
Max Range: ~10-75 meters (33-250 ft) indoor range, depending on power levels
Security: Stronger encryption, improved device authentication
Routing Efficiency: Unified standard, better compatibility across brands
Best For: Modern smart home networks with better device interoperability.

Why This Matters for Your Smart Home

If you’re running a Zigbee network, Zigbee 3.0 is the best choice for modern homes, as it ensures better device compatibility and performance. If you're looking ahead, making it easier to connect devices across different ecosystems.

Z-Wave 500 vs. 700 vs. 800: Why It Matters

Z-Wave has evolved significantly over the years, with newer chipsets offering better range, security, and efficiency. But if you’re mixing generations in your network, older devices might be holding you back.

Z-Wave 500 (Z-Wave Plus)

Released: ~2013
Max Range: ~100 meters (328 ft) open-air
Security: Optional S2 security
Routing Efficiency: Limited compared to newer models
Best For: Legacy systems; still works but lacks modern optimizations.

Z-Wave 700 (Z-Wave Plus v2)

Released: ~2019
Max Range: ~150-200 meters (492-656 ft) open-air
Security: S2 required by default
Routing Efficiency: Faster network healing and optimization
Best For: Those upgrading from older Z-Wave devices for better range and performance.

Z-Wave 800: The Future of Z-Wave

Released: ~2021
Max Range: Up to 1 mile (1600m) open-air
Security: S2 + SmartStart required
Routing Efficiency: Most optimized; lowest power consumption
Best For: Future-proofing; ideal for new networks.

Why This Matters for Your Smart Home

If your network still has Z-Wave 500 repeaters, they might be slowing down your newer 700/800 devices by forcing them to use lower speeds. To get the full benefits of modern Z-Wave, it’s best to replace older Z-Wave 500 repeaters with 700/800 models.

Why I Prefer Managing a Zigbee Network Over Z-Wave

After spending time managing both Zigbee and Z-Wave networks, I’ve found that Zigbee has a key advantage: native group support with multicast commands.

What Makes Zigbee Groups So Powerful?

• In Home Assistant, you can create Zigbee groups that allow devices to receive a single multicast command, making group actions instant.
• Example: Turning off all Zigbee lights in a room happens instantly rather than one-by-one.
• With Z-Wave, the same action often happens sequentially, causing noticeable delays.

Recommended Hardware & Software

Note: These devices are widely available on major online retailers like Amazon.

• SONOFF Zigbee 3.0 USB Dongle Plus (Model: ZBDongle-P) – A reliable and affordable Zigbee controller.
• ZOOZ 800 Series Z-Wave Long Range S2 USB Stick (Model: ZST39) – A future-proof Z-Wave controller with strong range.
• Home Assistant – The best open-source home automation software for flexibility and control.

Final Thoughts: Zigbee vs. Z-Wave

What’s your experience with Zigbee or Z-Wave? Have you run into delays like I did? Let me know your thoughts!

• Z-Wave excels in long-range reliability.
• Zigbee wins in instant, real-time group control.
• Upgrading to Z-Wave 700/800 helps fix some of its network limitations.

Both protocols have strengths, but if you want instant, synchronized device control, Zigbee is my top choice. Ever since I upgraded my Z-Wave controller and leaned more on Zigbee for group actions, my automations have gone back to being instant—just like they were in my small condo. If you’ve been frustrated by slow automations, looking at how your network handles unicast vs. multicast might be the key to fixing it.