Since i run a couple of features on my Raspberry PI 3 Model B i do run into heat issues it looks like.
Nothing of the features should give much load to the Raspberry PI.
I don’t think that it is normal that Home assistant should overload the Raspberry PI and come instable/unresponsive.
I run Z-Wave, Toon Eneco, RFXCOM, Unifi, App daemon, Tuya, Spotify.
When i touch the processor it is much hotter than normal. It doesn’t have it all the time it happens sometimes just overnight to become in this state.
I don’t know for sure if it is a heat problem or some other thing that does make it instable/unresponsive but i like to know what you should do if you run into certain problems.
How can i measure the temperature of the PI inside Home assistant?
Thanks for the help !
Remove that and watch the temperatures plummet. It’s a bit of a resource hog from memory. I removed it and bought a CloudKey - that thing runs HOT too.
With this sensor:
- platform: command_line
name: CPU Temperature
command: "cat /sys/class/thermal/thermal_zone0/temp"
unit_of_measurement: "°C"
value_template: '{{ value | multiply(0.001) | round(1) }}'
And it is unusual warm here. Since you run toon eneco, I can assume your from the Netherlands.
I think you are just about right. I do also have a cloud key and that thing does become hot indeed.
But i thought it was helpfull to also have it in Home assistant. Due to the lack of resources of the Raspberry PI i have removed it.
I also tried the sensor setting you mentioned but it doesn’t pop-up in my dashboard as an option. What can be different in my config?
I am pretty new so maybe some extra info how i can troubleshoot the issues myself should be helpfull 
I am indeed in The Netherlands But i don’t hope that my hardware will crush everytime it becomes above 30 degrees celsius. 
Do you use a shell with a fan or some heatsinks or something else to cool down your hardware?
On my raspberry Pi 4, I use one of these, and it stays within limits
My other raspberries just have a plastic case, and these have problems.
I think i will buy a case with heatsinks and a small fan. I think the combination of both should solve the issue. Do you have a recommendation? 
I don’t understand what you mean by this.
Did you put @tom_l’s code inside the sensor: section of your configuration.yaml file (or in the separate file if you are using packages) and then restart home assistant, then you should see it under Developer Tools → States