Here are my temperature readings with exactly the same number of processes running on Debian (Raspbian), I said that I disabled the GUI and no HDMI cable. So in a perfectly identical config.
- Raspberry pi without housing: 38 ° C 38.5 ° C
- Raspberry pi case with lego house (small air hole on the top): 42 ° C
=> And finally the Raspberry Pi with the housing purchased above 47.6 ° C to 48 ° C
Within 3 configurations the raspberry pi was placed on a glass desk.
So this case has increased the temperature by 5.6 ° C, which is pretty huge but normal since no ventilation on top, it would have been better to make small holes on top in addition to the below for ventilation.
Finally nothing serious, the raspberry pi can support up to 80 ° C, it seems to me that this is the maximum temperature supported by the memory components.
With ventilation on top, it would surely be the best case I've seen so far, certain other boxes have ventilation but are of lower quality, too bad.