Turn on a dim bathroom light at night
Walk in half asleep, get enough light to see, and do not wake the house. If it fails, the wall switch still works.
Best for: Bathrooms with a dimmable light and a sensor placed near the entry.
Not for: A bathroom where a short PIR timeout would turn lights off during a shower. A PIR sees movement, not a still person. Start with a longer timeout or use the PIR vs mmWave presence article to add occupancy sensing.
Why this exists
Bright bathroom light at 2am is miserable. This recipe uses only enough light to navigate safely, then hands the shutoff to the paired motion-lighting recipe. It should work without explaining a special night mode to a guest.
💡 For sensor positioning and coverage testing, see how to place motion sensors for reliable automations.
Logic
- Trigger: Bathroom or entry motion is detected.
- Conditions: Night mode is active or it is within your chosen night window, and optionally the room is dark enough.
- Action: Turn on the bathroom light at 10 percent. Set a warm color temperature only if the light supports it.
- Wait / timeout: The paired turn lights off after motion stops recipe owns the timeout. Start at 10 minutes for a shower bathroom.
- Stop condition: New motion cancels the shutoff. A manual wall-switch change wins.
- Manual override: The wall switch still wins.
What I used
Detect bathroom motion, humidity, temperature, and light
Aeotec TriSensor 8. Use the extra readings where they solve a real bathroom problem.
Dim a fixed light
TP-Link Tapo S505D Matter Smart Dimmer Switch. Verify hub compatibility. The physical paddle must remain usable.
See recommended gear for the job-first checklist. Amazon product links on this page are affiliate links, and I earn from qualifying purchases. Product recommendations and the affiliate relationship are explained in the disclosure.
Setup notes
Choose one understandable signal for nighttime behavior. A fixed night window is simplest. If the household already uses a reliable Night mode, the lighting rule can check that instead.
Do not infer Night mode only because someone entered a bedroom. Different schedules, illness, guests, and brief trips make that signal unreliable. If Night mode is not already dependable, use a fixed time window. See daily routine automations for deliberate night-mode patterns.
Platform notes
The platform must combine a motion trigger with a dependable night condition and set a specific dimming level. Keep the physical wall switch available, and let the separate no-motion rule own shutoff timing. See the platform guides for broader fit and maintenance tradeoffs.
Amazon Alexa
Build this as an Alexa routine only when the sensor appears as a motion trigger under When, the schedule can limit the routine to nighttime, and the light exposes brightness under Alexa Will. Amazon documents the underlying motion-sensor state model, but trigger and dimming choices still vary by device and region. Test the routine in the dark and keep shutoff in a separate routine.
SmartThings
Create an automatic SmartThings Routine with motion and a nighttime period as IF conditions, then set the dimmer level in the THEN action. Use location mode or illuminance instead of a fixed time only when that signal is already dependable. The available conditions and actions come from the device’s exposed SmartThings capabilities.
Hubitat
Use Hubitat Room Lighting to activate the bathroom light from motion and apply a low level by mode or time period. Keep the delayed shutoff and physical-change behavior explicit so shower activity and a wall-switch choice are not overridden.
Home Assistant
Home Assistant is a technical fit for combining motion, time or house state, and a dimming action, but I have not personally run it. Verify the current sensor and light integrations, then preserve the same low-light default, separate shutoff, and physical-control requirements.
Advanced features
Keep one nighttime level until the recipe is dependable. If the household needs different levels before bed and during deep night, add one extra time period rather than a complicated schedule. A warmer color temperature can feel less disruptive, but safe footing matters more than a particular number or color.
Use the separate turn lights off after motion stops recipe for shutoff behavior. Add another sensor or presence sensing only when normal shower use proves that the entry sensor is not enough.
Failure modes
- The light is too bright: Start at 10 percent, then test in a dark bathroom. Increase only enough for safe footing.
- It turns off during a shower: A PIR can miss a still person through steam or a shower curtain. Use the paired off recipe with a 10-minute starting timeout, or follow the PIR vs mmWave presence article to keep detecting a person after motion stops.
- The sensor sees a hallway instead: Aim and test the sensor so passing traffic does not light the bathroom unnecessarily.
- A guest uses the wall switch: Treat it as the final answer. The next automation must not immediately undo that choice.
- The hub or internet is down: The wall switch remains the fallback. Confirm that any relied-on Level 2 path is local.
FAQ
What brightness should a bathroom night light use?
Start at 10 percent, then test it in the dark. Raise it only enough for safe navigation.
Why does a bathroom motion light turn off during a shower?
A PIR sensor can miss someone who is still or hidden by steam and a shower curtain. Use a longer timeout or a presence sensor.
What happens if the hub or internet connection goes down?
The physical wall switch still works independent of the automation, so the bathroom light can always be turned on manually.