X3 on it having something like a AquaHot which uses diesel or electric for the energy source. It has 12V pumps/fans/control system and when boondocking... the diesel boiler for the heat source. The newer ones have two 120V heating elements like in a normal hot water heater so while on electric rarely would you have to use the diesel boiler. With only one element I'm good down to the low 20s in the morning before needing to turn the diesel boiler on.
I recently replaced my NOcold 1200 with a 21 cu ft refer posted here as a
DIY project...should have done it years ago. It uses 8 amps DC when running... less than a 100W electric bulb as they are that energy efficient.
It was only last year that I found a unit that I hoped would fit without any modifications to the cabinet. A Whirlpool WRT311FZDB in black came within 1/2" (too tall) of fitting and sticks out 4" further than the 1200 I replaced. I no longer monitor the temp several times a day as it's now a boring 34-36 all of the time. Like Executive I have to put the ice cream in the microwave to be able to dip it.:B