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.

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.

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.

Technical Report

Actual Savings and Performance of Natural Gas Instantaneous Water Heaters

To gain a better understanding of in situ performance, 24 natural gas water heaters were installed in ten Minnesota homes, then extensively monitored and tested under an alternating mode test procedure for 15 months.