The Sonoff ZBM5-1C-86W is a Zigbee-based smart wall switch aimed at homeowners who want local control, decent build quality, and flexibility in a standard 86mm form factor. On paper, it ticks a lot of boxes. In practice, the experience very much depends on how deep you're willing to go.

Who's Actually Buying This?

The ZBM5-1C-86W is showing up in smart home setups across the UK and Europe — particularly among people with older wiring who are trying to retrofit intelligence into their homes without rewiring everything. One Reddit user specifically picked up the ZBM5-1C-86W and its sibling ZBM5-3C-86W to tackle a two-way stair light circuit in a 1960s UK property. That's a real-world stress test if there ever was one.

If you're a Home Assistant user building a fully local Zigbee mesh — using something like the Sonoff Zigbee Dongle-E Plus — this switch slots in naturally. It's the kind of product that appeals to the crowd who discovered that cloud-dependent smart devices become "expensive dumb devices" the moment their ISP hiccups. That's a real and valid concern, and the Zigbee protocol here means your lights keep working even when the internet doesn't.

The Multi-Button Flexibility Is the Hidden Story

Here's something the product listing won't tell you: even if this is a 1-channel switch (controlling one relay), the extra buttons on the panel can be repurposed for anything you want — triggering automations, controlling other smart lights in the room, adjusting scenes, or even operating curtain motors. One user in the community has five of these switches in their home and uses the additional buttons to control curtains, toggle Netflix-mode scenes, and run AC routines. The middle relay handles the actual wired light; everything else is automation logic.

But — and this is a significant but — achieving that level of flexibility requires stepping away from the stock firmware.

The default firmware is where things get messy. The community consensus is pretty blunt about it: "the standard firmware of these sucks." The advice from experienced users is to flash ESPHome onto the device if you want meaningful customization. That unlocks per-button behavior, long-press actions, relay memory settings, and far more granular control. If you're not comfortable with firmware flashing, you'll be stuck with a more limited (and reportedly frustrating) out-of-box experience.

The Zigbee Ecosystem Advantage

Sonoff's Zigbee lineup has been steadily maturing, and the ZBM5 series benefits from that ecosystem momentum. Zigbee devices — especially Sonoff's — pair reliably with Home Assistant via the Zigbee Dongle-E Plus, and they function as mesh repeaters, strengthening your overall network as you add more devices. For anyone building out a multi-room setup, that matters a lot.

The 86mm wall plate format also means it physically fits into standard European and UK backboxes without adapters, which is a practical plus when you're dealing with older housing stock where depth can be tight.

Old Wiring Compatibility: Proceed Carefully

The real-world use case of fitting this into a 1960s UK circuit with two-way switching highlights something buyers need to take seriously: legacy wiring doesn't always cooperate with smart switches. Permanent live configurations, missing neutral wires, and older cable standards can all complicate installation. This isn't unique to the ZBM5-1C-86W — it's a known challenge with smart switch retrofits generally — but it's worth knowing before you buy.

If your home has conventional modern wiring with a neutral at the switch, you're likely fine. If you're working with older or unconventional circuits, do your homework first.

Who Should Buy This — and Who Shouldn't

This switch is a solid choice if you're already in the Home Assistant / Zigbee ecosystem, comfortable with a bit of technical setup, and want reliable local control without a monthly subscription. Flash ESPHome, set up your automations, and it becomes a genuinely capable device.

If you're a casual smart home user expecting a simple app-based setup with polished out-of-box behavior, the ZBM5-1C-86W will likely disappoint. The stock firmware limitations are a real barrier, and the learning curve is steeper than a typical smart plug or bulb.

Frequently Asked Questions

Q: Does the Sonoff ZBM5-1C-86W work without the internet?

A: Yes — that's one of its core advantages. As a Zigbee device integrated with Home Assistant, it operates entirely locally. Your lights will keep working even if your internet connection goes down.

Q: Can the extra buttons on the ZBM5-1C-86W control other smart devices?

A: Yes, but this requires either ESPHome firmware or Home Assistant automation logic. With the right setup, you can assign each button to trigger scenes, control other lights, operate curtains, and more — regardless of the wired relay.

Q: Is the default firmware good enough for most users?

A: Community feedback suggests the stock firmware is quite limited and frustrating. Experienced users strongly recommend flashing ESPHome for full functionality and customization.

Q: Does it work with UK 1960s two-way wiring?

A: It can, but compatibility depends heavily on your specific wiring configuration. Older properties with non-standard or neutral-less wiring may present installation challenges. Always verify your wiring setup before purchasing.

Q: What hub or controller does the ZBM5-1C-86W need?

A: It's a Zigbee device and works with any Zigbee coordinator. The Sonoff Zigbee Dongle-E Plus paired with Home Assistant is the most commonly recommended setup and offers full local control.