When I got mine I did some tests. I put a remote thermometer in the back and measured the temp with the pack in direct sunlight on an 80° day, the temperature rise was only a few degrees, I think the steel screen reflected a bunch of heat and when walking with the airflow caused by that it was negligible. I even put a $10 USB borescope camera in one of the grommet holes and I could watch her when walking on my phone...not needed but pretty cool.
(sure wish we had a parrotlet icon so I could stop pretending this wasn't a budgie)
