I set up a Circadian Lighting Automation in Home Assistant to match light in the house to the day. I wanted cooler, brighter light in the morning and daytime, and warm, dim light in the evening. This improves comfort and cuts late-evening stimulation. I will walk through the hardware choices, the Home Assistant integration options, and a straight‑forward automation pattern you can copy and adapt.
Choose tunable white lights. Tunable white bulbs let you change colour temperature in kelvin. Good picks are Philips Hue, IKEA TRÅDFRI tunable bulbs, or any Zigbee tunable white lamp running through a Zigbee gateway like ConBee II or a coordinator with ZHA or Zigbee2MQTT. You can use Wi‑Fi tunable bulbs too, but they often lag or disconnect more. Aim for devices that report brightness and colour temperature to Home Assistant; that makes automation simpler. For daytime set colour temperatures around 5,000–6,500 K and brightness near 100%. For evening pick 2,000–2,700 K and 20–40% brightness. Use a physical override switch or a simple scene so you can reject an automation that isn’t right for the moment.
Connect devices to Home Assistant. If you have Hue Bridge, add the integration and import lights. For Zigbee use ZHA or Zigbee2MQTT and join the devices. For Wi‑Fi devices check for native integrations or flash Tasmota where practical. Once the lights appear in Home Assistant test simple service calls: turn them on, change brightness, change colour temperature. If a light does not accept colour temperature, the automation will only be able to change brightness. I prefer grouping lights into room entities: light.lounge, light.kitchen. Create input_booleans for “Auto lighting enabled” per room if you want quick local control.
The automation pattern I use is simple and resilient. Use the sun integration for sunrise and sunset triggers with offsets, and use time triggers for mid‑day shifts. Add a presence or occupancy check if you want lights to skip when nobody is home. Give the action a transition so the changes are smooth. Here is a practical YAML example you can adapt; replace entity_id and the kelvin and brightness values to suit your lights.
yaml
alias: Circadian lighting — morning
trigger:
- platform: sun
event: sunrise
offset: “-00:30:00”
condition: - condition: state
entityid: inputboolean.autoloungelighting
state: “on”
action: - service: light.turnon
target:
entityid: light.loungegroup
data:
brightnesspct: 100
kelvin: 6000
transition: 600
For evening use a sunset trigger with a positive offset. Replace kelvin with lower values and set brightnesspct to 20–40. If you want gradual shifts through the day, add extra automations at mid‑morning and late afternoon, or use a custom integration such as Adaptive Lighting or the circadianlighting custom component. Those manage continuous transitions and handle manual overrides well. Test each scene at the actual time and adjust kelvin and brightness until the light feels right.
Tweak the details. Short transitions look abrupt. Long transitions avoid noticeable jumps but can be too slow if you leave a room. If someone is watching a film, the automation should respect a “cinema” scene. Use inputbooleans and simple templates to combine states, for example skip automation if inputboolean.movie_mode is on. Log failures. If a light fails to change, Home Assistant will show the last service call. Fix flaky devices by moving them closer to the coordinator or switching to a different protocol.
You will get the best result by starting small. Automate one room for a week and dial in values. Keep the controls obvious so anyone in the house can toggle automation off. After a short run you will have a functional Circadian Lighting Automation in Home Assistant that reduces blue light at night and gives bright, cool light when it helps you stay alert.
