An LCA starts by fixing two things that determine the whole answer: the functional unit (what the product does, like delivering 1,000 hours of light) and the system boundary, cradle-to-grave for the full life or cradle-to-gate when the study stops at the factory door. The team then builds a life cycle inventory of every material and energy flow, characterizes the impacts, and interprets the results. Two LCAs are only comparable when boundaries and functional units match, which is the first thing to check when a supplier hands you a flattering one. Environmental product declarations, increasingly requested in automotive and construction supply chains, are standardized summaries built on exactly this method.

The value for hardware teams is in trade-offs that intuition gets wrong. A lighter material can carry a dirtier production phase and still win on use-phase savings, or lose once end-of-life is counted, and an LCA is how you find out which. The results feed material selection, circular economy decisions like design for disassembly, and supplier requirements set through sustainable procurement. Keep the scopes straight: carbon accounting ledgers an organization's emissions year by year, a carbon footprint totals greenhouse gases for one product or entity, and an LCA examines a product across many impact categories at once.