profile may be used, as shown in Figure 14. The numerical values for normalized hourly hot water use can be found in the Building America Analysis Spreadsheet.
The combined hourly profile is based on a 1990 study conducted by Becker and Stogsdill (1990), which included hot water data from several earlier studies. The profiles for the clothes washer and dishwasher are based on the electrical end-use measurements in the End-Use Load and Consumer Assessment Program (ELCAP) study conducted in the Pacific Northwest by the Bonneville Power Administration in the 1980s (Pratt et al. 1989). The hourly profiles for the common laundry room hot water use are from the “Multi-Unit Residential Clothes Washer Replacement Pilot Project” produced by the City of Toronto (Lithgow et al. 1999). It is assumed that the normalized hourly profiles for electricity and hot water are the same for washing machines and dishwashers. The shower, bath, and sink profiles were taken from a study titled, “Residential End-Uses of Water” conducted by Aquacraft for the American Water Works Association (AWWA 1999). The central restroom profile stems from the office occupancy profile in the NREL Commercial Benchmark for a medium-rise apartment, in combination with engineering judgment (NREL 2009).
Fraction of Total Daily Usage
Hour of Day
Figure 6. Clothes washer hot water use profile