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

Gary Klein and Associates

Every day, across the United States, millions of gallons of water and millions of Btus of energy are lost in our hot-water systems through a combination of structural and behavioral waste.

Ours is an era where efforts to conserve resources have led to ever-increasing complexity, be it in water heaters that are harder to understand and use, be it in the smart grid and electric meters that tell the utility all about our behavior.

Given human nature, it is our responsibility to provide the infrastructure that supports efficient behaviors.

Gary Klein is tackling this issue in a different way, rejecting complexity and concentrating on elegant simplicity. He works to change building codes and to get architects and builders to use plumbing systems that, by their design, deliver hot water quickly and with minimal waste.

He has looked at the structural and behavioral waste and believes great resource savings are to be had in both.

When he gives a presentation, it's impossible to doze in the back row. He calls on people at random to serve as props, marks lines on the floor in tape, makes people think, and makes them laugh. It works.

GKA Services and Capabilities

The focus of GKA's work and what it strives to achieve.

Gary Klein Turned Me Into a Sink

People who have been in his presentations describe their experiences.


Gary Klein has written numerous articles on hot water distribution systems and how different elements affect the outcome.


Seeing is believing. Here you can find some of Klein's presentations that somebody thought to record.