Washing machines, refrigerators and ovens carry long alphanumeric model codes, and small differences in those codes separate machines that are otherwise the same. The structure is what makes comparison hard.
The code encodes more than the model
A typical appliance code combines a product family, a capacity or feature tier, and a set of trailing characters covering colour, door configuration, region and sometimes the retail channel.
Two machines identical in every mechanical respect can therefore carry different codes because one has a different handle finish.
Comparison tools match on the code, so those two machines never appear as alternatives to each other, and neither price is ever tested against the other.
Channel-specific variants are common
Large chains negotiate their own variant, which may differ only in a display panel, a programme name or a bundled accessory.
The manufacturer benefits by keeping retailers from competing directly on the same code, which protects everyone's margin at once.
For the shopper the effect is a market that looks well supplied but offers few genuine like-for-like comparisons.
Energy labels give a comparable measure
Efficiency labels are produced under a defined test procedure, which makes the stated consumption figures comparable across brands in a way marketing claims are not.
They also carry capacity and noise figures on the same basis, giving three independent points of comparison that do not depend on the model code.
Two variants with matching label figures across all measures are almost certainly the same machine, which is the most reliable way to identify them.
Feature names describe ordinary functions
Manufacturers apply proprietary names to common capabilities, so a standard function acquires a distinctive label that appears exclusive.
Comparing feature lists across brands then compares vocabulary rather than capability, and the machine with more named features is not necessarily better equipped.
Reading the manual, which is normally published online before purchase, describes what the function actually does in plain terms.
Servicing outlives the model code
Appliances are kept for many years, so parts availability and the density of local service engineers matter more than a modest price difference.
Parts are usually shared across a family of variants, which means a widely sold family is better supported than an unusual channel-specific version.
Choosing a mainstream variant from a well-represented family is therefore often the cheaper decision measured across the life of the machine.