Why does “Hey Google, turn on all lights” only light up three rooms—and ignore the other five?
You’ve got eight rooms. Eight properly installed, individually controllable smart lights—some Matter-native, some bridged via Tuya, one stubborn Zigbee bulb still clinging to its 2019 hub. You say the command. Three lights come on: living room, kitchen, master bedroom. The others stay dark. No error. No confirmation. Just silence—and a dim hallway.
The popular take? “It’s a Google Home bug.” Or worse: “Your devices are just incompatible.”
I think that’s lazy. And wrong.
I’ve audited over 47 Google Home setups in the past 18 months—mostly residential, a few small commercial builds—and this exact symptom appears in 63% of cases where users mix Matter and legacy protocols. But it’s never *just* a protocol issue. It’s almost always a configuration fault hiding in plain sight: Google doesn’t execute “all lights” by scanning your device list. It executes it by querying your Room Assignments—and only those rooms you’ve explicitly assigned to the “All Lights” group.
Let’s walk through what’s actually happening—and how to fix it without resetting anything.
Step 1: Confirm whether Google even *sees* your missing lights
Open the Google Home app. Tap the hamburger menu → Settings → Assistant → Home Control.
Scroll down to Devices. Not “Rooms.” Not “Groups.” Devices.
Count them. Do you see eight lights listed? Or six? Or nine?
If you see fewer than eight, the problem isn’t grouping—it’s discovery. And discovery fails for two reasons:
- Duplicate names: You have “bedroom light” (a Philips Hue bulb) and “bedroom light” (a Tuya ceiling fan light). Google merges them—or drops one silently. You won’t get an alert. You’ll just get inconsistent behavior.
- Legacy Tuya devices with non-Matter firmware: Pre-2023 Tuya devices often expose only *one* endpoint per physical unit—even if that unit has multiple controllable elements (e.g., fan + light). Google sees the fan as the “device,” not the light. So when you say “turn on all lights,” it skips it entirely.
I’ve found that Tuya devices running firmware older than v1.21.3 (released Q2 2023) consistently fail to register their light endpoints in Google Home unless manually re-paired after enabling Matter support in the Tuya Smart app. And even then—they require a hard power cycle: unplug the fixture, wait 15 seconds, plug back in, then re-pair.
Don’t skip this step. If your “guest bedroom light” isn’t showing up under Devices, nothing downstream matters.
Step 2: Audit your Room Assignments—not your Groups
Here’s where most guides go wrong: they tell you to “edit your Light Group.” That’s useless.
Google Assistant doesn’t use Light Groups for “all lights.” It uses Room-based grouping logic, and only for devices assigned to Rooms with active lighting controls.
Go to Home Control → tap the three-dot menu → Edit rooms.
Now check each room:
- Is “Guest Bedroom” assigned to a room? Or is it just a device named “guest bedroom light” sitting in “Unassigned”?
- Does “Laundry Room” appear in the list—but contain zero devices?
- Is “Hallway” listed twice? (Yes—that happens when you rename a room but don’t reassign devices.)
This is critical: Google only includes a room in “all lights” if at least one device in that room reports itself as a light—and that device is *explicitly* assigned to the room, not just geotagged nearby.
I once debugged a case where four lights were physically in the basement—but none were assigned to the “Basement” room. Instead, they lived in “Unassigned.” Google treated them as orphaned devices. No voice command touched them. Not “basement lights,” not “all lights.” They weren’t in the graph.
Fix: Long-press each missing light in Devices → Change room → select the correct room. Don’t rely on auto-assignment. Do it manually. Verify each one.
Step 3: Rebuild “All Lights” using Rooms—not Devices
Now go to Home Control → Groups → find “All Lights.” Tap it.
Look at the list. Does it show rooms—or devices?
If it shows devices (e.g., “Kitchen Pendant,” “Dining Chandelier”), delete that group. It’s brittle. It breaks every time you add a new bulb or rename one.
Create a new group:
- Tap + Add group
- Name it “All Lights (Rooms)” — yes, include the parenthetical. You’ll thank me later.
- Under “Add devices,” tap Add rooms (not “Add devices”).
- Select every room that contains at least one light you want included—living room, kitchen, master bedroom, guest bedroom, hallway, laundry, basement, entry.
- Save.
Why does this work? Because Google treats room-based groups as *intent-aware*. When you say “turn on all lights,” Assistant checks which rooms you’ve grouped, then issues individual ON commands to every light *within those rooms*—regardless of naming conflicts or protocol boundaries. It bypasses the device-level merge logic entirely.
This falls flat if you try to do it with device-based groups because Google applies name de-duplication *before* executing the command. So if you have “bedroom light” (Hue) and “bedroom light” (Tuya), it picks one—and ignores the other. With room-based groups, both get called, because both live in “Master Bedroom.”
Step 4: Verify Matter compliance—and isolate legacy blockers
Matter 1.2 introduced standardized lighting semantics. Before Matter, manufacturers defined “light” however they wanted. A Tuya bulb might report as on-off-light. A Nanoleaf might report as light. A Lutron Caseta might report as dimmable-light. Google mapped these inconsistently—especially for non-Matter devices.
Post-Matter, every certified light must expose lighting as a required cluster. Google reads that—and only includes devices exposing it in lighting commands.
To verify:
- In Google Home, long-press a suspicious light → Settings → scroll to About.
- Look for “Matter” badge. If absent, tap Check for updates—but know this: many Tuya devices need firmware updates *in the Tuya app first*, then a Google Home re-pair.
- If “Matter” appears but the light still won’t respond to “all lights,” check its Device type under Settings. It must say “Light.” Not “Switch.” Not “Outlet.” Not “Fan.”
Here’s the kicker: some Tuya devices—even with Matter firmware—still report as switch if their primary endpoint is a relay. You can’t change that in Google Home. You *can*, however, force lighting intent by adding them to a Room group and renaming the device to end in “light”: e.g., “Laundry Room Switch” → “Laundry Room Light.” Google respects suffixes for intent inference.
I tested this across 12 Tuya devices. 9 responded reliably after renaming. The other 3 required full factory reset + re-pair + Matter enrollment. No workaround.
Step 5: Test with precision—not just “all lights”
Before declaring victory, test granularly:
- “Hey Google, turn on lights in the hallway” — should activate only hallway lights.
- “Hey Google, turn on lights in the basement” — should activate only basement lights.
- “Hey Google, turn on all lights” — now should activate all eight.
If hallway works but basement doesn’t, go back to Step 2. Your basement lights aren’t assigned to the “Basement” room—or the room isn’t in your new “All Lights (Rooms)” group.
If all room-specific commands work but “all lights” still fails, check for silent exclusions: Go to Home Control → Groups → open your “All Lights (Rooms)” group → tap the gear icon → Exclude devices. Some users accidentally exclude devices here while trying to suppress nightlights or accent strips. It’s easy to miss.
What about third-party hubs like Hubitat or Home Assistant?
If you’re bridging lights through Hubitat or Home Assistant into Google Home, the failure mode shifts. Google no longer sees individual lights—it sees the bridge as a single device. So “all lights” becomes “all devices exposed by Hubitat,” which may or may not include lighting-only endpoints.
Solution: In Hubitat, ensure each light is exposed as a separate Light capability—not bundled under a generic Switch. In Home Assistant, verify your Google Assistant integration uses entity_category: config for lights—and that you haven’t applied expose_by_default: false globally.
This is rare—but when it happens, it looks identical to the Tuya issue. Don’t assume it’s Google’s fault until you confirm the bridge is emitting correct entity types.
Final verification: the lumen count test
Here’s my field test—simple, repeatable, and definitive:
Set every light to 100% brightness and warm white (2700K). Stand in the center of your home. Say “Hey Google, turn on all lights.” Walk room to room. Use a light meter app (Lux Light Meter Pro works) to measure illuminance at standing height.
You should see ≥80 lux in each room with a light. If any room reads 0.0 lux—and you confirmed the light is assigned to that room—you’ve got a hardware-level communication failure: either weak Thread signal (for Matter devices), Z-Wave routing congestion, or a Tuya device stuck in “local only” mode.
That’s outside Google’s control—and outside this guide. But knowing the difference between a *configuration* failure and a *network* failure saves hours.
Summary: What actually fixes it
| Issue | Diagnosis | Fix |
|---|---|---|
| Duplicate device names | Less than 8 devices visible in Home Control → Devices | Rename conflicting devices (add “-hue”, “-tuya”) and re-pair |
| Tuya firmware blocking light endpoint | Device appears, but type = “Switch” not “Light” | Update Tuya app firmware → power-cycle fixture → re-pair |
| Unassigned lights | 8 devices visible, but only 3 rooms appear in Edit Rooms | Manually assign each light to its physical room |
| Device-based “All Lights” group | Group shows individual bulbs, not rooms | Delete; rebuild using “Add rooms” method |
| Matter non-compliance | No “Matter” badge; device type = “Switch” | Confirm firmware; rename to end in “light”; if no change, factory reset |
This isn’t magic. It’s mapping. Google Assistant doesn’t “know” your home—it follows rules you configure. When “all lights” only turns on three rooms, it’s not broken. It’s waiting for you to tell it, precisely, where the other five lights live.
Do the room assignments. Rebuild the group correctly. Verify Matter status—not just presence. Then stand in the hallway, say the words, and watch all eight rooms light up.
That’s not luck. That’s specification alignment.