Trigger automation based on relative value

Configuration
1

Good afternoon,

I have an automation that turns on a fan when humidity reaches 69%, and shuts off when it goes down to 60%.

There is also a trigger to turn off fan if the humidity falls below 50%. This second off trigger is there in case I turn on the fan manually, but the humidity is already below 69%.

This works in the summer when humidity is high, but not so much in winter when humidity can fall way below.

I would like to change the trigger to be a relative based on other sensor.

Something like:

  • If fan OFF & inside humidity is above [outside humidity] x 1.2 then
    • trigger automation to turn fan ON.
  • If fan ON & inside humidity is below [outside humidity] x 1.1 then
    • trigger automation to turn fan OFF.

example 0:
outside humidity 45%
inside humidity 60%
fan off
trigger automation to turn fan ON as 60% is above 45% x 1.2, or 54%.

example 1:
outside humidity 45%
inside humidity 53%
fan on
trigger automation to turn fan OFF as 53% is below 45% x 1.1, or 49%.

My current automation is as follows:

alias: "Base: bath: Fan: ON/OFF on humidity"
description: Turn on fan if too humid, off if okay in basement bath.
mode: single
triggers:
  - entity_id: sensor.weathersensor5_humidity
    above: 69
    trigger: numeric_state
  - entity_id:
      - sensor.weathersensor5_humidity
    below: 60
    trigger: numeric_state
  - entity_id:
      - sensor.weathersensor5_humidity
    below: 40
    trigger: numeric_state
conditions: []
actions:
  - choose:
      - conditions:
          - condition: numeric_state
            entity_id: sensor.weathersensor5_humidity
            above: 69
        sequence:
          - type: turn_on
            device_id: ee952
            entity_id: f7369
            domain: switch
      - conditions:
          - condition: numeric_state
            entity_id: sensor.weathersensor5_humidity
            below: 60
        sequence:
          - type: turn_off
            device_id: ee952
            entity_id: f7369
            domain: switch

I have attempted something like:
above: "{{ state_attr('sensor.lumi_lumi_weather_humidity_2', 'humidity') * 1.2 }}"

in above, where the sensor is the external humidity sensor, but no such luck.

Thank you and Merry Christmas and Happy New Year!

2

Rather than putting it all in the automation, have you tried creating a template binary sensor to handle the relative values? Then the trigger would be a simple on/off.