Environmental assessment of the durability of energy-using products: method and application

Durability of products is generally seen to be a desirable goal. However, the extension of the lifetime of energy-using products is not necessarily the optimal strategy, as the efficiency of products generally decreases with wear, and their substitution by more energy-efficient products can be more environmentally beneficial in the long run. There is currently no standardised approach to resolving this conflict. The article describes an original method for environmentally assessing the durability of energy-using products in order to identify if and to what extent the potential extension of the productʹs lifetime could have life-cycle benefits. The method is based on the comparison, within a life-cycle perspective, of two scenarios of different lifetimes of a target product and its potential substitution with better performing alternatives. The method considers some key parameters of durability, including the productʹs lifetime, energy consumptions, impacts of lifetime extension and characteristics of the replacement product. The method can be used for ecodesign purposes by manufacturers or by policy makers. The applicability and robustness of the method are discussed, including limitations, difficulties and possible improvement. A general index and a simplified index have been introduced. The applicability and relevance of the simplified durability index is shown in two case-studies (of washing machines). The article shows that some life-cycle environmental benefits can be gained by extending the lifetime of the products. However, the benefits are variable, mostly depending on the selected impact category, the extension of the lifetime, the impact of repair, and the efficiency of the replacement product.