Get cheapest time window

Use this action to find the cheapest consecutive time window for a job that takes between 0.5 and 24 hours, such as running the dishwasher or charging a battery. It hands the result back in a response variable, so you can use it in later steps of the same automation or script.

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.

This action returns data instead of changing something in your home, so it needs somewhere to put its result. Pair it with a template sensor, like in the Find the cheapest time for your dishwasher example.

To find the cheapest time window 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. From the search box, search for and select Green Planet Energy: Get cheapest time window.
6. Set Duration to how many hours the job takes.
7. Optional: set Time range to limit the search to daytime or nighttime hours.
8. Select Save.

This action does not support targets. In the UI, you are not prompted to choose an area, device, entity, or label.

Options in the UI

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 green_planet_energy.get_cheapest_duration. Store the result in a response variable so you can use it in later steps:

action: green_planet_energy.get_cheapest_duration
data:
  duration: 3.5
  time_range: night
response_variable: cheapest

Options in YAML

Response data

The response is a mapping describing the cheapest window that was found:

• duration: The requested duration in hours.
• average_price: The average electricity price in EUR/kWh across the window.
• start_time: The start of the window, in ISO 8601 format.
• end_time: The end of the window, in ISO 8601 format.
• hours_until_start: How many hours remain until the window starts.
• time_range: The time range that was searched.

Example response:

duration: 6.25
average_price: 0.1985
start_time: "2026-06-20T11:00:00+02:00"
end_time: "2026-06-20T17:15:00+02:00"
hours_until_start: 13.3
time_range: day

Good to know

• The window always starts on the hour, even though prices are published in 15-minute slots.
• If you leave Time range empty, the whole day is searched.

Try it yourself

Ready to test this? Open Settings > 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.

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:

• Get energy prices: Fetches upcoming 15-minute electricity price slots from Green Planet Energy.