The Showerhead Comparison Calculator is designed to compare the water, energy and carbon costs of showerheads with different water efficiency ratings. The calculator is targeted toward residential water users and provides a potent tool for educating the public on the energy and greenhouse gas emissions associated with their water use, since showering is among the most energy-intensive end uses of water.

Users begin by selecting the appropriate state to determine the carbon intensity of their electric grid. If using a natural gas water heater, click on the “Natural Gas” tab at the bottom of the page to open the natural gas worksheet. After selecting the flow rate of their current showerhead, users then fill in the number of people in their household, the number of showers each person takes per week, and the duration of each shower. The user then selects the flow rate of a more efficient showerhead to determine the water, energy and greenhouse gas emissions they could save. Users are encouraged to adjust the frequency and length of their showers to compare how showering habits can affect their water and energy use, in addition to using a more efficient showerhead.

To use this tool, data is entered on the left-hand side of the screen and the results display to the right of the white divider line. The data and assumptions behind this tool can be viewed by clicking on the “Assumptions” tab in the bottom left corner of the workbook. Please note that these models are designed for educational purposes and are not intended to provide a comprehensive analysis of a given scenario.