Air Filter Countdown

Introduction

This project creates a sensor that tracks when the HVAC filter is changed, and sends an alert when it needs to be changed 90 days later.

I'm using a Wyze sense door sensor to trigger the automation when the filter cover is opened, but any door sensor can be used. I set up the the Wyze sensors using this integration: (https://github.com/kevinvincent/ha-wyzesense)

I used one of HA’s helpers to set up a input_datetime entity. I created this in the UI by going to Configuration/Helpers and clicking the add button, then “Date and/or time.” I then added a name, in my case “Air Filter Date Installed”. This entity will be used to set the date that the air filter was changed.

A template sensor needs to be set up in order to calculate the days after an input date, and there will also be an actionable push notification on iOS, so configuration.yaml must include the following:

configuration.yaml:

### Required Sensors ###
sensor:
- platform: time_date
  display_options:
      - 'time'
      - 'date'
      - 'date_time'
      - 'date_time_utc'
      - 'date_time_iso'
      - 'time_date'
      - 'time_utc'
      - 'beat'
      
- platform: template
  sensors:
    air_filter_life_remaining:
        value_template: >
          {{(((as_timestamp(states.input_datetime.air_filter_date_installed.state) + (90 * 86400) ) - as_timestamp(states.sensor.date.state)) /86400)|round(0)}} days
    
###For Actionable Push Notification###
ios:
  push:
    categories:
      - name: Air Filter Confirm
        identifier: 'airfilterconfirm'
        actions:
          - identifier: 'CONFIRM_AIRFILTER'
            title: 'I changed the filter.'
          - identifier: 'CANCEL_AIRFILTER'
                title: 'I did not change the filter.'

About the template sensor:

I really struggled with this part in the original project, and after posting on Reddit, received some much appreciated guidance from u/DER31K which can be seen in the comments of the linked post. Essentially, I couldn't figure out how to get a template to add 90 days to a date, but if you convert the date to a timestamp, it becomes much easier to work with. This bypasses the need for the python script entirely, and makes this whole project much simpler. u/DER31K's template is explained below. 86400 is seconds in a day.

{{(((as_timestamp(states.input_datetime.air_filter_date_installed.state) + (90 * 86400) ) - as_timestamp(states.sensor.date.state)) /86400)|round(0)}}

So this is.... Date filter last changed + 90 days - today's date = days until the next filter change based on it needing be to done 90 days after the last filter change.

Automations:

The first automation will send an actionable notification when the HVAC filter cover is opened. This is triggered by the Wyze door sensor, and prompts me to confirm the filter was changed. If you wanted, you could skip the actionable notification and just have the sensor trigger set the date that the filter was changed directly (essentially combining this automation with the next), but I wanted to have the extra control in case the filter cover was opened for any other reason.

- alias: Air Filter - Open Detected - Send iOS Actionable Notification
  description: ''
  trigger:
  - entity_id: binary_sensor.wyzesense_77842647
    platform: state
    to: 'on'
  condition: []
  action:
  - data:
      data:
        push:
          category: airfilterconfirm
      message: Did you change the AC filter?
      title: AC Filter Cover Opened
    service: notify.mobile_app_iphone

Then I need an automation to actually set the date triggered by my notification action. This uses the service input_datetime.set_datetime.

- alias: Air Filter - Set Date
  description: ''
  trigger:
  - event_data:
      actionName: CONFIRM_AIRFILTER
    event_type: ios.notification_action_fired
    platform: event
  condition: []
  action:
  - data_template:
      date: '{{ as_timestamp(now())|timestamp_custom(''%Y-%m-%d'') }}'
    entity_id: input_datetime.air_filter_date_installed
    service: input_datetime.set_datetime

Lastly, I need an automation that reminds me when the countdown is done and I need to change the filter again. I have it set up to remind me either when I get home or at 5 pm if I am already home.

- alias: Air Filter - Filter Needs to Be Changed
  description: ''
  trigger:
  - entity_id: person.me
    event: enter
    platform: zone
    zone: zone.home
  - at: '17:00:00'
    platform: time
  condition:
  - below: '1'
    condition: numeric_state
    entity_id: input_datetime.air_filter_date_installed
    value_template: '{{(((as_timestamp(states.input_datetime.air_filter_date_installed.state)
      + (90 * 86400) ) - as_timestamp(states.sensor.date.state)) /86400)|round(0)}}'
  - condition: zone
    entity_id: person.me
    zone: zone.home
  action:
  - data:
      message: The AC Filter is due to be changed.
    service: notify.mobile_app_iphone

Air Filter Sensor Card

To add a custom card in lovelace, I created the following sensor using the picture-elements card.

elements:
  - entity: input_datetime.air_filter_date_installed
    style:
      bottom: 52%
      color: black
      font-size: 26px
      left: 4.5%
      transform: initial
    type: state-label
  - entity: sensor.air_filter_life_remaining
    style:
      bottom: 6%
      color: black
      font-size: 26px
      left: 4.5%
      transform: initial
    type: state-label
  - entity: automation.air_filter_set_date
    state_image:
      'off': 'https://i.imgur.com/jsXMqex.png'
      'on': 'https://i.imgur.com/jsXMqex.png’
    style:
      left: 80%
      top: 50%
      width: 25%
    tap_action:
      action: none
    type: image
image: 'https://i.imgur.com/OutUp0O.png’'
type: picture-elements