INVESTIGATING WATER AND ENERGY SAVING TECHNOLOGIES WITH RESPECT TO CARBON DIOXIDE EMISSIONS AND WATER CONSUMPTION

U.S. households consume 80% of all energy used and are responsible for a similar share of CO2 emissions. The U.S. electric system emits approximately 40% of all domestic greenhouse gases (GHG) and contributes to greater than 40% of freshwater withdrawals. This GHG intensity of U.S. households highlights the importance of reducing GHG emissions at household levels. While many household energy and water consumption saving appliances are commercially available, the tradeoff resulting from implementing various appliances and technologies is not well understood due to the lack of comprehensive measures for those technologies. The objective of this report is to determine consumption and emissions data for a total of 18 household appliances and fixtures. A metric tons of carbon dioxide equivalence, mtCO2e, per kilowatt hour (kWh) is used as a measure of GHG emission impact. The mtCO2e is calculated based on specific residential fuel sources used for electricity generation. The 18 household appliances and fixtures include both conventional and those certified as energy and water-efficient by the US EPA. Of the technologies investigated, the greatest water savings are acquired by switching to an Energy Star clothes washer, a dual flush converter and a high-efficiency toilet. Likewise, the greatest energy savings are acquired by switching to an Energy Star clothes washer and a tankless hot water heater or propane water heater. The mtCO2e emissions impacts determined in this study will be inputs for a role-playing game[1] in which the tradeoffs associated with using various water and energy-saving appliances and technologies will be holistically studied in the context of household food, energy, and water consumption behavior