Light groups in Zigbee2MQTT or Home Assistant? How to choose

You have four spots in the living room and you want to control them as one light. There are two places to do that, and you can see the difference with your own eyes: one way they come on together, the other way they come on one after another. Which to pick depends on what else has to go in that group.

A Zigbee group, in Zigbee2MQTT

A group you create in Zigbee2MQTT exists in the Zigbee network itself. One command goes out as a multicast to all the bulbs at once.

• Upside: your lights switch genuinely simultaneously, with no popcorn effect, and you load your network less because one message goes out instead of four.
• Downside: it only works for Zigbee devices. A bulb from another system cannot join.

Use this for lights that always switch together, like all your ceiling spots or a row of pendants above the table.

A group in Home Assistant

A Light group helper in Home Assistant addresses each bulb separately.

• Upside: you can combine anything, so Zigbee next to Wi-Fi next to Gira next to Hue, and across integrations.
• Downside: your lights respond just after one another. With two bulbs nobody notices; with eight they do.

Use this for a "whole room" group that pulls different systems together.

A group around a single light: get rid of it

An old trick was to put one bulb in a group of its own, so you could replace the bulb without touching your automations. You no longer need that layer once you use logical names in Zigbee2MQTT: replace the bulb, give the new one the same friendly name, and everything keeps working.

So keep groups only where they genuinely bundle several lights. The rest is maintenance that buys you nothing.

Scenes over groups

If you want fixed light levels per room, like "Standard", "Dimmed" and "Night light", define those in scenes rather than in your automations. Let automations and buttons only call the scene. When you want to adjust a level you then do it in one place, and it is right everywhere afterwards: on your dashboard, on your button and in your voice command.

Frequently asked questions

Can a bulb be in several Zigbee groups? Yes, for example in "ceiling spots" and in "whole living room". Keep the number down, though, because some bulbs have a limit and will not tell you politely when they hit it.

Will I see a Zigbee2MQTT group in Home Assistant? Yes. Every group shows up automatically as a light entity, and you control it just like a single bulb.

Should I build scenes in Zigbee2MQTT or Home Assistant? In Home Assistant. There you can include lights from other systems and call the scene from automations, buttons and dashboards. See also IKEA buttons on scenes.