Heterogeneous Residential Water and Energy Linkages and Implications for Conservation and Management

Abstract

This paper develops an integrated approach to model heterogeneous household water and energy use and their linkages. The approach considers variations in behavioral and technological water and energy use factors that affect U.S. indoor residential water and energy use for toilets, showers, faucets, clothes washers, and dishwashers. The study uses a recent, large, national, disaggregated household water use data set collected from 11 cities, as well as national energy data on water heater efficiency and setpoint/intake temperatures. First, probability distributions of water and energy use factors are identified and correlated. Then, Monte Carlo simulations are used to calculate probability distributions for estimated household water and energy use. Finally, linear regressions are used to find the relative effects of water and energy factors on household energy use. Results show that water and energy distributions among households are skewed, with the largest 12% of the users consuming 21% and 24% of water and energy, respectively. Water heater setpoint temperature followed by intake temperature, heater efficiency, shower hot water percentage, household size, shower flowrate, and faucet flowrate have the highest relative effect on household energy use and should be targeted to reduce household energy use. The approach improves prior homogenous and deterministic water-energy models and can help utilities select and size cost-effective, collaborative water and energy conservation actions.