Final Report: Intelligent, Networked, Retrofittable Water Heater Controller
The Gas Technology Institute (GTI) in collaboration with Center for Energy and Environment (CEE) conducted a CARD-funded field study to validate the performance, cost-effectiveness, and direct energy savings of the Aquanta, a smart water heater controller introduced to the market in 2016. Thirty-three (33) Aquanta smart water heater controllers were retrofitted onto 11 residential electric storage water heaters and 22 on residential gas storage water heaters. Ten sites were fully monitored with measurement and verification (M&V) instrumentation to validate the technology’s ability to save energy and to accurately monitor daily water and energy usage. The field evaluation validated the ease of installing the controller with most installations taking between 60 and 90 minutes to complete. The controller was found to save energy two ways. First, the controller reduces the energy lost from storing hot water by lowering the tank temperature set point and eliminating unnecessary reheats. Second, the controller reduces the amount of energy delivered to the fixture by eliminating or reducing over heating (i.e. less mixing). There also was a noticeable shift in Energy Use Profile. Savings from the controller averaged 2.3% by one analysis method and 9.3% by another, but individual results ranged considerably. The wide variability in savings in both analyzes suggest the need for a larger population of sites and an increased length to the monitoring period in order to obtain more robust results.