Monitor freezer

I am looking for a way to monitor our freezer. This morning the 5th time over the last years I discovered that someone in our house did not close the freezer correctly one or two days before. So I had to throw away almost everything … I am looking for a solution to monitor the freezer. Unfortunately It only has a red status LED “!” - nor sirene. The most obviouds way, using am door/window sensor does not seem to be the right way. The door is open only for one mm. Enough for sucking in warm air from outside…
So monitoring this Led could be a solution, but how? I also thought of monitoring the power consumption. Any suggestion how to do this? Or any other suggestions? For wireless compontenes I have running z-wave, zigbee, and Homematic.

I use a power monitoring smart plug. If the compressor runs (power > x) for longer than y minutes send a notification. Also if the compressor has been off for longer than z minutes send a notification (it usually runs a few times an hour).

One final automation: if the switch is turned off, turn it on again immediately. It’s hidden from the dashboard and is set to come on after power failure so this is just a safeguard.

Sound´s great. I have running Tasmota, Shelly and Fibaro Smart Plug´s. The Tasmota´s currently are not willing to talk via MQTT… but the Shelly´s and the Fibaro´s are working fine.
How have your realised the rules / coding? I am not that familiar with writing code… I can read and understand most of it and can adddept it… I have done some work in node red.
For saving and visualising of some data I have first experiences with influx and grafana…

It’s just a numeric state trigger.

  - platform: numeric_state
    entity_id: sensor.your_power_sensor
    above: 10 # or whatever value is good to detect the compressor running
      minutes: 30 # make this longer than the maximum run time you normally see
  - service: notify...etc

Likewise for the hasn’t run for ages alert:

  - platform: numeric_state
    entity_id: sensor.your_power_sensor
    below: 10 # or whatever value is good to detect the compressor not running
      hours: 3 # make this longer than the maximum gap between compressor runs you normally see
  - service: notify...etc

I do use these sensor putting in the freezer:
[Xiaomi Aqara Temperature Smart Air Pressure Humidity Environment Sensor Remote Control Zigbee Work For Gateway Hub Homekit APP|Smart Remote Control| - AliExpress]

And check on temp > then your minimum
Works perfect for me

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I did use a door switch for this, when open for more, than 2 minutes, every mobile device of the family get’s a notification.

Last months with our new freezer i use the same timing, but the door switch is already a part of the LG freezer with WiFi, using the SmartThinkQ HACS integration.

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Here is the automation i use now:

alias: Koelkast deur te lang open
description: ''
  - type: opened
    platform: device
    device_id: 63b33aef118b11eb9281afb567acd2c3
    entity_id: binary_sensor.koelkast_door_open
    domain: binary_sensor
      hours: 0
      minutes: 2
      seconds: 0
condition: []
  - service: notify.mobile_app_mischa_op6t
      message: 'Hallo, de koelkast staat nog open. Wil je even kijken?'
  - service: notify.mobile_app_in2013
      message: 'Hallo, de koelkast staat nog open. Wil je even kijken?'
mode: single

Could you tell how long the battery will last?

I do have 2 freezers and 2 fridges.
The minimum is half a year. I do have some longer then a year.
One is over 1,5 years already
The battery level is dropping to about 40% in a couple of weeks but stays there for at least half a year.
I was supprised about the duration myself

That’s awesome, going to move one of the sensors to my freezer!

Has anyone try Aqara Temperature sensor inside freezer?

I have add mine and it gets unavailable every 2nd day.
I wonder if is just the freezer that cuts the signal off or something else ???

Anyone else has find a better way to monitor freezer temperature ??

I used that too. But the unit isn’t moisture proof enough and the battery will give up if the freezer gets too cold. So fridge: fine, freezer: not fine.

I now replaced it with an Inkbird IBS-TH2 and lithium batteries. Bluetooth is not close enough, so I use an ESP32 as a bluetooth proxy. Works great, the only downsize it that it is bigger than the Aqara, but for me it fits when I stick it on the backside behind a drawer.

I do. Into 2 Freezers. (-24degrees and -18 degrees)
The aqara battery stays for at least 6 months.
Never a problem

How do you include the bluetooth device into Home Assistant? I’m also plan to monitor the temperature of my refrigerator / freezer. Do you know how long the batterie lifes if there a temperatur of -18° celcius?

Battery life I cannot tell yet, other than it worked fine the last 4 months or so at an average of -19.5 degrees Celcius. I placed an Esp32 with a bluetooth proxy nearby and the device was discovered by Home Assistant automatically.

My freezer does a periodical cycle where temp hit a very low point for a short time (can’t remember exact limit). After that the Aqara would keep reading the same value until I reset it. Tries several batteries, both CR and BR which should be able to handle lower values.

I just got a few of these and put one of them in the freezer, it lasted about 4 days before it stopped responding.

I assumed it was because the operating range is supposed to be -20C to +60C, but it seems some users have got them to work OK, so not sure why it stopped.

If you want more than one, get from AliExpress as they discount quiet well on multiples.

I know this is an old thread but I wanted to post a working solution in case anyone else finds this thread in the future.

After messing with the various ready made sensors I followed a YouTube video that walked through using ESPhome, an ESP32 or ESP2866 and a couple of Dallas DS18B20 temperature sensors.

Very easy to follow - Monitor Equipment Temps with the Dallas Temp Sensors, ESPHome, Home Assistant and Grafana - YouTube

The sensors read from -55C to +125C and cost £2 on AliExpress, and the wiring/soldering is simple.

Had them running in my fridge/freezer for about two weeks now and they have worked perfectly.


Nice solution. I guess you have the module with ESP32 outside the freezer? If so, how do you get the cable with the temperature probe into the freezer itself without too much leakage?

Sorry just seen you question.

Yes the ESP32 is outside the fridge/freezer, and the cables are thin enough to not cause any noticeable leakage. I was worried about this issue so I run the cable in from the hinge side of the door so the seam is always pushed on under pressure when the door is closed.

If you were concerned you could probably shorten the wires and run flat cable, or even just strip the cable back so the individual wires without the protective sleeve are in the join.