This study evaluates and provides guidance on improving the life cycle environmental performance of dishwashing in the typical U.S. household. Typical user behaviors and recommended best practices for manual dishwashing as well as machine dishwasher use are evaluated. A sensitivity analysis shows the influence of varying grid carbon intensity, water heater type, regional water scarcity, and behaviors such as pre-rinsing and machine loading on overall results. Use-phase behaviors are observed through a small-scale laboratory study. Dishwashing following typical manual and machine practices produces 5,620 and 2,090 kg CO₂e life cycle greenhouse gas (GHG) emissions respectively based on washing 4 loads (8 place settings per load) a week for 10 years. Avoiding typical behaviors like pre-rinsing and selecting heated dry can decrease life cycle GHG emissions for machine dishwashing by 3% and 11%, respectively. The running tap style of manual dishwashing results in the highest life cycle GHG emissions of the alternatives in the lab study. Manual dishwashing has the potential to have the lowest GHG emmisions (1,610 kg) when recommended behaviors are followed, less than the 1,960 kg CO₂e for recommended machine dishwasher use. When life cycle water consumption burdens are evaluated, typical manual and machine dishwashing use 34,200 and 16,300 gallons respectively and these results are contextualized to regions with different water scarcity. A life cycle cost (LCC) analysis finds that machine dishwashing costs more than manual dishwashing over a 10-year lifetime even if best practices are followed. However, when a user’s time spent washing is valued, machine dishwashers pay for themselves within a year of use.

这项研究评估并为改善典型美国家庭洗碗的生命周期环境绩效提供了指导。评估了手动洗碗机以及机器洗碗机的典型用户行为和建议的最佳做法。敏感性分析显示了变化的网格碳强度，热水器类型，区域缺水情况以及预冲洗和机器负载等行为对总体结果的影响。通过小规模的实验室研究可以观察到使用阶段的行为。按照典型的手动和机器操作进行洗碗，可产生5,620和2,090 kg CO ₂生命周期温室气体（GHG）排放分别基于10年每周清洗4个负载（每个负载8个位置设置）。避免诸如预冲洗和选择加热干燥之类的典型行为，可以将机器洗碗碟机的生命周期温室气体排放分别减少3％和11％。在实验室研究中，手动洗碗器的连续水龙头形式可导致最高寿命周期的温室气体排放。遵循建议的行为时，手动洗碗可能会产生最低的GHG排放量（1,610千克），少于1,960千克CO ₂e供推荐的机器洗碗机使用。在评估生命周期中的用水量负担时，典型的手动和机器洗碗机分别使用34,200加仑和16,300加仑，并且这些结果将根据不同的缺水地区而定。生命周期成本（LCC）分析发现，即使遵循最佳实践，在10年的使用寿命中，机器洗碗的成本也要比手动洗碗的成本高。但是，当珍惜用户花费的洗涤时间时，机器洗碗机会在使用一年内收回成本。