I just received my fairphone 3 a few days ago and I have to say that I am in love with this phone. (I come from a Nexus 5)
I have concern about it’s warmth in normal usage. In daily use when using the phone the highlighted area in the pic bellow feels hot, and when monitoring the phone heat can go up to near 50°C.
To my knowledge, the fairphone is supposed to not have difficulties with heating.
I want to know if my fairphone 3 have a problem with heating. But I did not find much data about this topic.
Here is a pic of a review from Les numériques, a French tech reviewing website, where the phone was kept during a moment with the camera on. Here we can see that the heat do not exceed 35°C in the problematic area in my phone.
Here is a thread but the problem seems to be not related. My fairphone is updated the the last available update.
Here is a Reddit thread in which people discuss about this subject, but there is no more details.
Something that could be a way to help me could be to share here the temperature of your fairphone 3 and of the room/region where you are for several times in your daily use? For the phone temperature you can use the (proprietary) app CPU monitor or this if you prefer open source free softwares.
If someone have info about this topic, I would be glad if they can share.
Maybe I would have to join the support, but before I do that I prefer to ask here.
Here is some data for my case:
46°C with a weather temperature of 31°C
55°C when in a church
40°C when in a room at 27°C
Have a good day!