Reports & Materials


Demand Control Systems Deliver Efficiency in Commercial Hot Water Use

Technical overview of the effectiveness of new demand control systems to reduce heating and pumping costs from hot water circulation in hospitality and commercial venues.

Technical Report

Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test

Four high-efficiency natural gas water heaters were installed in homes to characterize their savings potential, installed efficiencies, and abilities to meet household demands.


Field Study of an Intelligent, Networked, Retrofittable Water Heater Controller

This presentation was given at the 2017 ACEEE Hot Water Forum.


Combi Systems: Lessons Learned from the Field

Introduction to the technology and a discussion of lessons learned from a 200 system install project. Presented at the Presented at the ACEEE 2015 Hot Water Forum.


Tankless Water Heaters Update

Updates on water quality and installation issues, efficiency and savings, occupant satisfaction, and impact on gas distribution presented at the MN Blue Flame Gas Association Expo.


Tankless Water Heaters - Do They Really Save Energy?

Technical Report

Tankless Water Heaters: Do They Really Save Energy?

The in situ efficiency of the storage water heaters was nearly 20% lower than rated, while that of the tankless water heaters was only 10% lower. This paper will discuss the causes, consequences, and possible ramifications of this reduced efficiency.


Tankless Hot Water Heater Animations

Watch these animations for a deeper understanding of how tankless water heaters function within systems.

[CMSAbstractTransformation.DataBind]: Object reference not set to an instance of an object.

Technical Report

Measured Residential Hot Water End Use

High-resolution data on draw volume, length, flow rate, and spacing both overall and by hot water end use; based on data collected in ten homes in the Minneapolis/St. Paul metro area.

Technical Report

Application of a Linear Input/Output Model to Tankless Water Heaters

This study evaluates the applicability of a linear input/output model to gas-fired, tankless water heaters. The model can be used to reproduce performance metrics, such as the energy factor, and can be used to evaluate the impacts of alternative draw patterns and conditions.