Turn on water heater

Use this action to turn on a water heater, for example to start heating water before you need it.

Using this action from the user interface

If you prefer building automations and scripts visually, Home Assistant walks you through this action step by step. You pick what to target, tweak a few options, and save. No YAML knowledge required.

To turn on a water heater from an automation or a script:

1. Go to Settings > Automations & scenes.
2. Open an existing automation or script, or select Create automation > Create new automation.
3. If you’re setting up a new automation, add a trigger in the When section. Scripts don’t need a trigger. They run when something else calls them.
4. In the Then do section, select Add action.
5. Select what you want to control. Under By target (see Targets), select the water heater you want to turn on.
6. From the actions shown for that target, select Turn on water heater.
7. Select Save.

Options in the UI

This action has no additional options beyond the target.

Using this action in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this action as water_heater.turn_on. A basic example looks like this:

action: water_heater.turn_on
target:
  entity_id: water_heater.demo

This turns on water_heater.demo.

Options in YAML

This action has no additional YAML options beyond the target.

Targets of the action

This action requires a target. The target is the object of the action. You can point the action at a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label, and Home Assistant will run the action on every matching water_heater entity behind that target.

• Entity: one specific water_heater entity, such as water_heater.living_room.
• Device: every water_heater entity that belongs to a device.
• Area: every water_heater entity in a room or area.
• Floor: every water_heater entity on a floor.
• Label: every water_heater entity that shares a label.

You can also select different target types in one action. For example, you can add a specific entity and an area as targets in the same action to run the action on both of them at once.

Good to know

• This action only works with water heater entities.

Try it yourself

Ready to test this? Open Developer tools > Actions, search for this action, fill in the fields, and select Perform action. You see what happens on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] without writing a line of YAML.

More examples

Real scenarios where this action shows up in automations and scripts. Copy any example and adapt it to your setup.

Automation: turn on a water heater in the morning

Turn on a water heater at a set time, for example to have hot water ready before you wake up.

• Trigger: Time: 06:00
• Action: Turn on water heater
  • Target: Utility room water heater

- alias: "Turn on the water heater in the morning"
  triggers:
    - trigger: time
      at: "06:00:00"
  actions:
    - action: water_heater.turn_on
      target:
        entity_id: water_heater.utility_room

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the action you’re calling and what you expected to happen, or share on our subreddit /r/homeassistant.

Related actions

These actions work well alongside this one:

• Turn off water heater: Turns off a water heater.

• Set water heater target temperature: Sets the target temperature of a water heater.

• Set water heater operation mode: Sets the operation mode of a water heater.

• Set water heater away mode: Turns away mode on or off for a water heater.