I guess that not having other warm objects pointing at the water, will not warm the water (example: a wall radiates infrared so it heats the water if the wall h

I guess that not having other warm objects pointing at the water, will not warm the water (example: a wall radiates infrared so it heats the water if the wall has "sight" over the water). Insulating the walls of the container with the water servers the same purpose - not have the water get heat from the surroundings.