A Cambro says it loses 1 degree an hour. I'm not sure what kind of holding times you're looking for, but if you put piping hot food in a cambro, it'll be piping hot hours later unless you open and close it alot. The cold side I'm not as familar with, but I would think the same would apply. The blue ice wouldn't hurt. If nothing else, you can pre cool, or pre heat prior to putting foods in.
honestly, I didn't know how to answer, I use a Cambro only for holding, if I am not careful, I can get food to continue cooking in a cambro, I wouldn't add any heat to the device at all.
trust me, you will never have a problem of holding heat, ever. (disclaimer,,, I only held meat, longest, 8 hours, still pipping hot!)
I've got a used MPC 400 with a gasket that leaks a little at the top of the door. It will still hold temps very well, like up to 8 hours with no problem.
FYI - most HD's will not allow you to hold food in a cambro for longer than 4 hours. Neeed a commercial holding unit with heating elements. I looked at them but can jut use the cambro as I don't hold that long.
Cambro brick red ultra pan carrier for 8" deep pans when you need a quick and easy way to store or transport one full size food pan of hot or cold food. Thanks!