AWWA ACE65131

This slide presentation outlines a discussion of four myths about water-efficiency of lavatory faucets, toilet fixtures and water heaters. Myth #1 claims that sensor-activated (e.g., infrared) lavatory faucets are water-efficient and yield water savings over traditional manually operated faucets. An outline of three studies is provided that includes: ASHRAE, 2002 (study of 106 to 120 days use) - volume increased 58% when manual faucets replaced with sensor-activated faucets (infrared);Millenium Dome, 2002 (1 yr study of 361 washbasin-faucets) - volume (per visit) with sensor-activated (infrared) was twice that of manual faucets; and,EBMUD, 2006-07 - study compares sensor-activated with manual faucets, andpreliminary findings show 20%+ more water consumed with sensor-activated installations. Myth #2 claims that the maximum faucet flow rate allowed in non-residential (commercial) installations in the U.S. is 2.2-gpm (8.3-Lpm) at 60 psi. Plumbing Code Provisions (UPC & IPC) are provided. Myth #3 claims that reduced flush volumes in toilet fixtures results in degraded performance and double-flushing. Background information on toilet fixtures is outlined, and conclusions on reduced flush volumes in toilet fixtures were: today's ultra low-flush toilets (ULFTs) and high-efficiency toilets (HETs) work;criticisms usually refer to old ULFT models (1992-97);double-flushing (DF) is a bogus argument;DF has existed since flushing toilets were invented;DF was common among 3.5-gpf (13-Lpf) fixtures;DF will exist in cases where demands on fixture are extraordinary; and,DF is usually caused by excessive paper and bowl cleaning. Myth #4 claims that homes with tankless water heaters (TWH) will use less water than homes with conventional storage water heaters. Claims about performance of tankless water heaters are provided and include: more (continuous) hot water available results in longer showers;warm-up period for TWH results in more cold water waste (that does not occur with continuously hot storage tank heater); and,TWH not proven cost-effective for the end-user. Principles and characteristics of gas TWHs are listed, and conclusions were that: when compared with storage tank water heaters, tankless water heaters do NOT result in lower household water consumption;do NOT provide "instantaneous" hot water at all end-use applications;are MORE COSTLY to install;require MORE MAINTENANCE; have an uncertain physical lifetime in North America;are being "oversold" by manufacturers promising what cannot be delivered;TWHs should NOT be considered as water-efficient or as worthy of water utility subsidies; and,TWHs should NOT be recommended as a water-efficiency strategy within a green building program. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2007

Number of Pages:

42

File Size:

1 file , 1 MB