What varies among the individual products is energy efficiency, in two ways — intrinsic efficiency of the mechanism’s use of energy in doing whatever the mechanism does, plus the efficiency of the user’s consumption of the output of that mechanism.

A multi-compartmented refrigerator might have the same efficiency of compressor/cooling system, but users more efficiently consume the “cool” by exposing a smaller proportion of the interior to the warmer outside environment when retrieving something or storing something.

Other use-efficiency effects can include:
* Using up the perishables before an extended trip, and pulling its plug while gone. If the trip is long enough recooling it after uses less energy than it would have used keeping its cool the whole time.
* Keeping the surrounding environment cooler. Opening the windows on cool nights does so without consuming electricity elsewhere (unlike, say, air-conditioning the place).
* Avoiding having significant breezes, from windows or fans, in the kitchen at times when the fridge is opened. The less the air moves around, the less mixing will occur near the refrigerator door.

All of those are user-behavior effects but not influenced by the fridge design.

A fridge design effect could include door aerodynamics that reduce mixing of air volumes due to air currents and vortices generated by the motion of the door. A design whose door did not swing open but rather rolled, garage-door style, might be better (or, perhaps, worse) in this regard.

A kitchen design effect exists, too. Running cold water pipes behind the refrigerator may improve its efficiency as the coils at the rear have an easier time dumping heat that way. The geometry of the kitchen could encourage the air near the refrigerator to stagnate rather than be breezy. The kitchen as a whole could be located in the basement, where it will tend to be cooler than otherwise, and the fridge and pantry area could even be placed in an uninsulated cellar separated by an insulated door from the rest.

Designing the plumbing and air ducts and general layout to conduct heat coming off the stove away from the refrigerator also makes sense; a basement kitchen could even feed heat rising from the stove into ducts to the rest of the structure to supplement the furnace.

On the other hand, putting the kitchen in the basement would break quite a lot of tradition.