Use Phase Impact

Use phase environmental impact varies 100x between product categories. Active products dominate lifecycle emissions: Electric vehicles consume 70-80% of lifecycle energy during use (150,000 km × 0.2 kWh/km = 30 MWh over 10 years vs. 10 MWh manufacturing). Refrigerators use 400 kWh/year × 15 years = 6 MWh vs. 1 MWh manufacturing. Data centers operate 8,760 hours/year consuming megawatts continuously. Passive products have minimal use-phase impact: Furniture, hand tools, and structural materials consume zero energy during use—their entire impact is embodied in manufacturing. Buildings are hybrid: structure is passive, but HVAC systems are active (50-70% of building lifecycle emissions). Efficiency degrades over time: HVAC systems lose 1-3% efficiency annually without maintenance. Vehicle fuel economy drops 0.5-1% per year. Hard drives slow down, CPUs throttle due to thermal paste degradation. Poor maintenance cuts lifespan 30-50% and increases energy use 10-30%. Grid decarbonization improves all active products: An EV charged on coal grid (0.9 kg CO2/kWh) emits more than a hybrid car. Same EV on renewable grid (0.05 kg CO2/kWh) is 90% cleaner. Grid improvements flow through to entire installed base—every electric appliance gets cleaner each year. Behavioral factors dominate utilization: Shared cars (car-sharing) have 10x higher utilization than private ownership—spreading manufacturing impact across more km. Thermostats adjusted 2°C save 10% HVAC energy. Right-to-repair legislation extends smartphone lifespans 2-3 years.