Sounds a product makes can affect that product's commercial value. It is important to understand what makes customers sense a product sound as connoting value, the amount of that value, and what acoustic features affect this evaluation. The present study conducted psychoacoustical experiments on such issues. An experiment investigating the structure of evaluation of vehicle door-closing sounds revealed hierarchical relationships between factors related to perceived emotional benefits (e.g., a feeling of security) and functional benefits (e.g., being solidly made) at higher levels, and factors related to acoustic features (e.g., abundant low-frequency components) at the lowest level. These benefits seem to affect consumers' purchasing behaviours. Major hierarchical structures related to these benefits appear capable of informing the design direction of door-closing sounds. Additionally, two experiments assuming customers' product selection were conducted regarding home appliances (vacuum cleaners and hairdryers). One experiment employed a contingent valuation method to estimate the value added to a product through sound quality improvement. The results suggest awareness of the considered price and the indication of sound output when purchasing, and previous experience of being distracted by product noise, affect whether participants accept a product with improved sound quality. The other experiment, adopting conjoint analysis, showed that improvement in sound quality and noise reduction increase the perceived utility of products, although the product price was regarded as the most important attribute. The results suggest sufficient design of product sound will affect customers' selection of a product. Non-acoustic factors such as indication of sound output also appear important in enhancing the value of a product's sound.