Weather-based boiler mode recommendation for Home Assistant. Analyzes the upcoming forecast and triggers a customizable action (notification, light, etc.) when your heating mode should change. No automatic switching — you stay in control.

README.md

Heating Mode Recommendation Blueprint for Home Assistant

A Home Assistant automation blueprint that analyzes the upcoming weather forecast and suggests when to manually switch your boiler between Heat, Hot Water, and Off (solar-only) mode — so you stop forgetting to do it yourself.

Designed for setups where the boiler mode must be changed physically (e.g. by pressing a button on the unit), but you still want smart, weather-aware reminders without switching multiple times a week.

How it works

Every morning at a configurable time, the blueprint fetches a daily weather forecast (up to 7 days) and evaluates three conditions:

Recommendation	Condition
Heat	Avg. daily high < 13 °C or overnight low < 5 °C
Hot Water	Neither Heat nor Off conditions are met
Off	Avg. daily high ≥ 18 °C and overnight low ≥ 10 °C and ≥ 3 sunny days (solar reliable)

All thresholds are configurable via the UI — no YAML editing required.

If the recommendation differs from the currently tracked boiler mode, your custom action fires. If they already match, nothing happens.

Vacation mode (optional)

When vacation mode is active, the recommendation is always Off — unless the overnight low drops below a configurable frost protection threshold for at least a configurable number of days, in which case Heat is recommended to protect pipes from freezing.

Requirements

• An input_select helper that tracks the current physical boiler state (3 options matching the labels configured in the blueprint)
• A weather integration that provides daily forecasts with temperature and templow fields

Recommended weather integrations (no API key required):

• Met.no – built into Home Assistant, works out of the box
• Open-Meteo – 7-day horizon, available via HACS

Setup

1. Add the blueprint to Home Assistant
2. Create (or reuse) an input_select helper with options matching the mode labels:

input_select:
  heating_mode:
    name: "Boiler Mode"
    options:
      - "Off"
      - "Hot Water"
      - "Heat"
    icon: mdi:thermometer-auto

3. Optionally create an input_boolean helper for vacation mode:

input_boolean:
  vacation:
    name: "Vacation Mode"
    icon: mdi:beach

4. Update the helper manually whenever you physically switch the boiler — this keeps the recommendation logic accurate
5. Create an automation from the blueprint and configure your action

Action

The blueprint accepts any Home Assistant action — notification, light color, TTS, persistent notification, etc. The following template variables are available inside your action:

Variable	Example value
{{ recommendation }}	Heat
{{ current_mode }}	Hot Water
{{ reason }}	Avg. high: 9.4 °C | Overnight low: 3.1 °C | ☀️ 2/5 sunny days
{{ vacation_mode }}	true

Example: Actionable mobile notification

- action: notify.mobile_app_your_phone
  data:
    title: "🔥 Boiler mode change suggested"
    message: >
      Switch to {{ recommendation }}
      (currently: {{ current_mode }}) — {{ reason }}
    data:
      actions:
        - action: "HEATING_CONFIRM"
          title: "✅ Done, I switched it"
        - action: "HEATING_LATER"
          title: "⏰ Remind me later"

To update the tracked mode when you confirm, add a companion automation:

trigger:
  - platform: event
    event_type: mobile_app_notification_action
    event_data:
      action: HEATING_CONFIRM
action:
  - action: input_select.select_option
    target:
      entity_id: input_select.heating_mode
    data:
      option: "Heat"  # Replace with the option value you switched to

Configuration reference

Input	Default	Description
Weather Entity	—	Any weather.* entity with daily forecasts
Heating Mode (input_select)	—	Tracks the current physical boiler state
Label – Heat	Heat	Must match the input_select option exactly
Label – Hot Water	Hot Water	Must match the input_select option exactly
Label – Off	Off	Must match the input_select option exactly
Daily Evaluation Time	07:30	When the forecast is checked each day
Forecast Horizon	5 days	How many days to average (1–7)
Heat – Max. avg. daily high	13 °C	Below this → Heat recommended
Heat – Max. overnight low	5 °C	Below this → Heat recommended regardless of highs
Off – Min. avg. daily high	18 °C	Must exceed this for Off to be recommended
Off – Min. overnight low	10 °C	Must exceed this for Off to be recommended
Off – Minimum sunny days	3 days	Minimum sunny/partly cloudy days for solar reliability
Vacation Mode Switch	(optional)	input_boolean that forces Off when active
Vacation – Frost protection threshold	-10 °C	Overnight low below this triggers Heat despite vacation mode
Vacation – Frost protection min. days	2 days	How many days must breach the frost threshold to override vacation mode
Reason Template	(optional)	Custom template for {{ reason }}; supports avg_high, min_low, sunny_count, _days, vacation_mode, frost_day_count
Action on Mismatch	—	Any HA action; has access to recommendation, current_mode, reason, vacation_mode

heating-mode-recommendation.yaml

blueprint:
  name: "Heating Mode Recommendation (Weather Forecast)"
  description: >
    Calculates a daily heating mode recommendation based on the weather
    forecast and triggers a fully customizable action when the recommendation
    differs from the currently tracked mode.


    **Available template variables in the action:**

    - `{{ recommendation }}` – e.g. "Heat", "Hot Water", "Off"

    - `{{ current_mode }}` – value currently stored in the input_select

    - `{{ reason }}` – short human-readable summary with temperature stats

    - `{{ vacation_mode }}` – true if vacation mode is active

  domain: automation
  author: "Nico Wiedemann <nico.wiedemann@gmail.com>"
  input:

    # ── Core entities ────────────────────────────────────────────────────────
    weather_entity:
      name: Weather Entity
      description: >
        The weather forecast entity (e.g. `weather.forecast_home`).
        Must provide daily forecasts with `temperature` and `templow` fields.
        Recommended: Met.no (built-in, no API key) or Open-Meteo (7-day horizon,
        no API key, available via HACS).
      selector:
        entity:
          domain: weather

    heating_mode_entity:
      name: Heating Mode (input_select)
      description: >
        The input_select helper that tracks the current physical state of the
        boiler. Its options must exactly match the three mode labels configured
        below.
      selector:
        entity:
          domain: input_select

    # ── Mode labels ──────────────────────────────────────────────────────────
    value_heat:
      name: Label – "Heat"
      description: >
        Exact option string in the input_select that represents full heating
        mode (space heating + domestic hot water).
      default: "Heat"
      selector:
        text: {}

    value_hot_water:
      name: Label – "Hot Water"
      description: >
        Exact option string in the input_select that represents domestic
        hot-water-only mode (boiler active, no space heating).
      default: "Hot Water"
      selector:
        text: {}

    value_off:
      name: Label – "Off"
      description: >
        Exact option string in the input_select that represents the off / solar-only
        mode (boiler off, solar thermal handles domestic hot water).
      default: "Off"
      selector:
        text: {}

    # ── Schedule ─────────────────────────────────────────────────────────────
    evaluation_time:
      name: Daily Evaluation Time
      description: Time of day at which the recommendation is recalculated.
      default: "07:30:00"
      selector:
        time: {}

    forecast_days:
      name: Forecast Horizon
      description: >
        Number of upcoming days included in the calculation.
        Longer horizons reduce switching frequency; 4–7 days recommended.
      default: 5
      selector:
        number:
          min: 1
          max: 7
          step: 1
          unit_of_measurement: days
          mode: slider

    # ── Thresholds: Heat ─────────────────────────────────────────────────────
    threshold_heat_high:
      name: "Heat – Max. avg. daily high"
      description: >
        If the average daily high across the forecast period falls **below**
        this value, "Heat" is recommended.
      default: 13
      selector:
        number:
          min: 0
          max: 20
          step: 0.5
          unit_of_measurement: °C
          mode: slider

    threshold_heat_low:
      name: "Heat – Max. overnight low"
      description: >
        If the coldest overnight low across the forecast period falls **below**
        this value, "Heat" is recommended regardless of the daily high.
      default: 5
      selector:
        number:
          min: -10
          max: 15
          step: 0.5
          unit_of_measurement: °C
          mode: slider

    # ── Thresholds: Off (solar-only) ─────────────────────────────────────────
    threshold_off_high:
      name: "Off – Min. avg. daily high"
      description: >
        Average daily high must reach **at least** this value before
        "Off" can be recommended.
      default: 18
      selector:
        number:
          min: 10
          max: 35
          step: 0.5
          unit_of_measurement: °C
          mode: slider

    threshold_off_low:
      name: "Off – Min. overnight low"
      description: >
        Coldest overnight low must be **at least** this value before "Off"
        is recommended (prevents cold mornings without heating backup).
      default: 10
      selector:
        number:
          min: 0
          max: 20
          step: 0.5
          unit_of_measurement: °C
          mode: slider

    min_sunny_days:
      name: "Off – Minimum sunny days"
      description: >
        Minimum number of forecast days classified as sunny, partly cloudy,
        or windy for solar thermal to be considered reliable enough to
        recommend "Off".
      default: 3
      selector:
        number:
          min: 1
          max: 7
          step: 1
          unit_of_measurement: days
          mode: slider

    # ── Vacation mode (optional) ─────────────────────────────────────────────
    vacation_entity:
      name: Vacation Mode Switch (optional)
      description: >
        A boolean helper (e.g. `input_boolean.vacation`) that, when turned on,
        forces the recommendation to "Off" — unless frost protection kicks in.
        When this switch is turned on, the recommendation is evaluated
        immediately instead of waiting for the next scheduled evaluation time.
        Leave empty to disable this feature.
      default: ""
      selector:
        entity:
          domain: input_boolean

    frost_threshold:
      name: "Vacation – Frost protection threshold"
      description: >
        If vacation mode is active and the overnight low on at least the
        configured number of days drops **below** this value, "Heat" is
        recommended instead of "Off" to protect pipes from freezing.
      default: -10
      selector:
        number:
          min: -20
          max: 5
          step: 0.5
          unit_of_measurement: °C
          mode: slider

    frost_days:
      name: "Vacation – Frost protection min. days"
      description: >
        Minimum number of forecast days with an overnight low below the frost
        threshold required to override vacation mode and recommend "Heat".
      default: 2
      selector:
        number:
          min: 1
          max: 7
          step: 1
          unit_of_measurement: days
          mode: slider

    # ── Reason template (optional) ───────────────────────────────────────────
    reason_template:
      name: Reason Template (optional)
      description: >
        Customizes the `{{ reason }}` variable available in your action.
        Useful for localization or a different format.
        Available sub-variables: `{{ avg_high }}`, `{{ min_low }}`,
        `{{ sunny_count }}`, `{{ _days }}`, `{{ vacation_mode }}`,
        `{{ frost_day_count }}`.
        Leave empty to use the default English format.
      default: ""
      selector:
        template: {}

    # ── Action ───────────────────────────────────────────────────────────────
    notify_action:
      name: Action on Mismatch
      description: >
        Executed when the recommendation differs from the current mode.
        The following variables are available inside your action templates:

        `{{ recommendation }}` – the suggested mode label

        `{{ current_mode }}` – the mode currently set on the boiler

        `{{ reason }}` – a short stats summary (avg high, overnight low, sunny days)

        `{{ vacation_mode }}` – true if vacation mode is currently active
      selector:
        action: {}


# ── Triggers ─────────────────────────────────────────────────────────────────
trigger:
  - platform: time
    at: !input evaluation_time
  - platform: homeassistant
    event: start
  # Fire immediately when vacation mode is turned changed (only if entity is configured)
  - platform: state
    entity_id: !input vacation_entity


# ── Actions ──────────────────────────────────────────────────────────────────
action:
  # 1. Fetch the daily weather forecast
  - action: weather.get_forecasts
    target:
      entity_id: !input weather_entity
    data:
      type: daily
    response_variable: forecast_raw

  # 2a. Input variables and raw forecast slice
  - variables:
      _weather_id:      !input weather_entity
      _mode_id:         !input heating_mode_entity
      _days:            !input forecast_days
      _val_heat:        !input value_heat
      _val_hw:          !input value_hot_water
      _val_off:         !input value_off
      _thr_h_high:      !input threshold_heat_high
      _thr_h_low:       !input threshold_heat_low
      _thr_off_high:    !input threshold_off_high
      _thr_off_low:     !input threshold_off_low
      _min_sunny:       !input min_sunny_days
      _vacation_entity: !input vacation_entity
      _frost_threshold: !input frost_threshold
      _frost_days:      !input frost_days
      forecasts: >
        {{ forecast_raw[_weather_id].forecast[:_days] }}

  # 2b. Derived calculations (references variables from 2a)
  - variables:
      temps_high: >
        {{ forecasts | map(attribute='temperature') | list }}
      temps_low: >
        {% set lows = forecasts | selectattr('templow', 'defined')
                                | map(attribute='templow') | list %}
        {{ lows if lows | length == forecasts | length
           else forecasts | map(attribute='temperature') | list }}
      avg_high: >
        {{ (temps_high | sum) / (temps_high | length) }}
      min_low: >
        {{ temps_low | min }}
      sunny_count: >
        {{ forecasts
           | map(attribute='condition')
           | select('in', ['sunny', 'partlycloudy', 'windy'])
           | list | length }}
      # Number of days where overnight low drops below the frost threshold
      frost_day_count: >
        {{ temps_low | select('lt', _frost_threshold) | list | length }}
      # True if vacation entity is configured and currently active
      vacation_mode: >
        {{ _vacation_entity != "" and states(_vacation_entity) == "on" }}

  # 2c. Decision logic (references all variables from 2a and 2b)
  #     _reason_template is loaded here so its sub-variables are already defined
  - variables:
      _reason_template: !input reason_template
      recommendation: >
        {% if vacation_mode %}
          {% if frost_day_count >= _frost_days %}
            {{ _val_heat }}
          {% else %}
            {{ _val_off }}
          {% endif %}
        {% elif avg_high < _thr_h_high or min_low < _thr_h_low %}
          {{ _val_heat }}
        {% elif avg_high >= _thr_off_high
                and min_low >= _thr_off_low
                and sunny_count >= _min_sunny %}
          {{ _val_off }}
        {% else %}
          {{ _val_hw }}
        {% endif %}
      current_mode: "{{ states(_mode_id) }}"
      reason: >
        {% if _reason_template | trim != "" %}
          {{ _reason_template }}
        {% else %}
          {% if vacation_mode %}
            🏖️ Vacation mode |
            {% if frost_day_count >= _frost_days %}
              ❄️ Frost warning: {{ frost_day_count }} days below {{ _frost_threshold }} °C |
            {% endif %}
          {% endif %}
          Avg. high: {{ avg_high | round(1) }} °C |
          Overnight low: {{ min_low | round(1) }} °C |
          ☀️ {{ sunny_count }}/{{ _days }} sunny days
        {% endif %}

  # 3. Abort if the recommendation already matches the current boiler mode
  - condition: template
    value_template: "{{ recommendation | trim != current_mode | trim }}"

  # 4. Run the user-defined action with recommendation/current_mode/reason in scope
  - choose: []
    default: !input notify_action