C OMMERCIAL S HOWERHEAD M ETERING S TUDY April 5, 2011 Regional Technical Forum Presented by: Michael Baker SBW Consulting, Inc.

Study Objective Statistically reliable estimates of electrical energy savings from the installation of low-flow showerheads on showers operated within commercial buildings. 2 4/5/2011

Possible Market Segments Hospitality (Guest rooms). Health (Assisted Living and various types and nursing and convalescent care). Businesses that provide shower facilities for employees. Dormitories Recreational (community centers, swimming pools, health clubs) 3 4/5/2011

Measure Specification Propose to use Sunbeam unit 4 4/5/2011

Results from Cascade Water Alliance Pilot 5 4/5/2011 Shower room total measured for public pool and community center

Research Plan Random sample of King County commercial parcels (Tax Assessor database) Telephone interview  Are there showers in the building that get regular use?  Fuel used for water heating? (supplemented by SBW direct install database) Random selection of showers in regular use with electric water heat, by market segment 6 4/5/2011

Sample Size Based on variance observed in metering of single family shower use 7 4/5/2011

Measurement Procedure Three visits to each site for engineering data  First visit Select random shower head One-time flow measurements Install TOU flow meter  Second visit Download and check pre data Install new low flow showerhead  Third visit Download and check post data Restore old head if requested Satisfaction survey 8 4/5/2011

Metering Design Time of use flow metering for individual shower heads Allows comparison of pre and post shower duration Clark Solutions Model CLXC-150-H-S, dry type, single-jet totalizing water meter. Provides a digital output signal for every gallon of water used. Onset model U9-001 event logger records the date and time each gallon of water used. 9 4/5/2011

Savings Analysis Identify separate shower events in time-series Compute number of shower events in pre and post and average gallons per event Estimate total events per year using full record  adjusted to reflect information about the daily, weekly and seasonal operating schedule obtained from facility staff Estimate mixed water temperature 10 4/5/2011

More Savings Analysis For pre and post conditions: Annual energy use (kWh/year/head) = Annual Mixed water use(gal/year) * [Mixed Water temperature (°F) – Cold Water temperature (°F)] * Density (8.33 lb./gal) * Specific Heat (1 Btu/lb. °F) ÷ Domestic hot water efficiency ÷ 3413 Btu/kWh. Savings is the difference between annual pre and annual post Compute market segment average savings 11 4/5/2011