Detergent is considered more efficient than soap in laundry primarily because it works better in hard water. While soap can form insoluble precipitates (soap scum) in hard water, reducing its effectiveness, detergents contain surfactants that do not react with hard water ions. This allows detergents to maintain their cleaning power even in challenging water conditions.

Additionally, detergents often include enzymes and chemicals specifically designed to target a wide range of stains, such as grease and protein, making them more effective at stain removal.