Energy savings from a comprehensive multi-family DHW retrofit program.

This paper documents the experimental results and energy savings estimate from an end-use and water metering study of a sample of 104 multi-family sites. These sites were treated with a comprehensive Domestic Hot Water (DHW) retrofit consisting of flow efficient 2.0 GPM showerheads, kitchen and bath aerators, tank thermostat setback to 130°F, and a tank wrap if necessary. These measurements were modeled by a regression model with variables for occupancy, setback degree, and delta flow at the primary showerhead. The model was used with actual measure installation records to extend the results of the study sample to the full participant population, in excess of 25,000  participants. The mean savings for the whole participant population at actual observed measure installation rates was 930 kWh per year per site.