Diagram of trunk and twig recirculation system with demand pumps, and a photo of Gary Klein


What You Don’t Know You Don’t Know about Hot Water Systems

Once we build a very high performance building from the perspective of heating, cooling and ventilation and install high efficiency lighting and plug loads, we are left with what to do about hot water. Hot water is a system: heater, distribution piping, plumbing fixtures and appliances, waste heat that runs down the drain. Overlay occupant behavior and then change technologies from what we are used to. To top it off, the way most of us were taught to design hot water systems is based on information that is more than 20 years out of date. This session will present practical measures you can incorporate into your next project that result in high performance hot water systems and very satisfied customers.

Tech lab for water heaters

We will demonstrate the principles, not just discuss them! As part of this session we will use the United Association’s Mobile Service Tech Training Lab to demonstrate some of the key principles and components of the most effective hot water systems. Using “live water”, both hot and cold, we will measure the pressure drop through pipe of different diameters, with and without 90 degree elbows and compare our results to the numbers in standard tables; we will measure that it takes 1.5-2.5 times the actual volume in a pipe for hot water to arrive at the other end, energy and time too; we will demonstrate how pressure compensating orifice aerators outperform fixed orifice aerators at low operating pressures.

Learning Objectives

  1. Identify at least 5 things you didn’t know you didn’t know about hot water.
  2. Understand the differences and similarities between hot water systems in different residential and commercial occupancies.
  3. Use the research to assess the selection of components of a hot water system.
  4. Learn hot to delivery hot water within 15 seconds, everywhere in any building, every time someone opens a tap, in an energy-efficient way.
  5. Develop a list of best practices for “hot-water-as-a-system” that can be implemented in upcoming projects.

This fast-paced, 2-hour event is intended for architects, engineers, builders, plumbers, pipe fitters, technicians, instructors, inspectors and raters who want an introduction to the latest in technology and research.

We have limited seating for 15 people per session so register soon. Wear comfortable shoes.

Sponsored by PG&E


Please select the session that works best for you:

UA Local 442
4842 Nutcracker Ln
Modesto, CA 95356

April 19, 12:30 p.m. -- Session 1
April 19, 2:30 p.m. -- Session 2
April 20, 8:30 a.m. -- Session 3
April 20, 12:30 p.m. -- Session 4
April 20, 2:30 p.m. -- Session 5

Pipe Trades Training Center
780 Commercial Drive
San Jose, CA 95112

May 17, 12:30 p.m. -- Session 6
May 17, 2:30 p.m. -- Session 7
May 30, 12:30 p.m. -- Session 8
May 30, 2:30 p.m. -- Session 9
May 31, 8:30 a.m. -- Session 10
May 31, 12:30 p.m. -- Session 11


UA Local 342 Plumbers Pipe Fitters
935 Detroit Avenue
Concord, CA 94518 

June 5, 12:30 p.m. -- Session 12
June 5, 2:30 p.m. -- Session 13
June 6, 8:30 a.m. -- Session 14
June 6, 12:30 p.m. -- Session 15 
June 14, 12:30 p.m. -- Session 16
June 14, 2:30 p.m. -- Session 17
June 15, 8:30 a.m. -- Session 18
June 15, 12:30 p.m. -- Session 19