I just purchased the Engel MR040 Marine fridge. I installed it is my Smittybilt scout trailer. It is in an enclosed compartment ( you can see the pictures in the Smittybilt scout trailer thread here on EP)
It pulls 3 AMP at startup @ 13.6 Volts, That decreases to 2.5 Amps as the compressor have been running for a minute. After the compressor switches off , in this case @ 35 deg. F, inside, the draw drops to 0.1 amps for the fans inside the unit. I let it run with the door closed for several hrs, and it was 74 deg inside, and after 5 hrs, the temp was only @ 75 deg. F. I presume this was in fact due to the garage temperature heating up, not the fridge, as it went to 75 deg, in the first 30 minutes, but stayed level at 75 deg. F. I know the compressor in the Engel, uses less energy and radiates less heat than any of the other ones, but I thought I would offer my testing of the Engel, with respect to mounting it inside an enclosed box. After my testing, I have decided not to vent the cabinet. Hope this helps you a bit.
Erling