Northwest Energy Efficiency Alliance

Case Study

Water Heater Efficiency Study

PowerWise provided the Northeast Energy Efficiency Alliance (NEAA) with SiteSage energy management equipment to monitor electricity use of heat pump water heaters. PowerWise also created online reports to help evaluators interpret the heat pump water heater performance data.

According to ECOFYS, who prepared the report for NEEA, the project was conducted for the purpose of providing the US Department of Energy with data to assist rulemakers in creating new electric water heater efficiency standards set to take effect in April of 2015.

Below is a screen from the Building Monitoring dashboard

The study covered 20 installations of five types of water heaters throughout Cowlitz County in the state of Washington.

From the report:

“Real-time data was collected into a database and data portal through PowerWise, a commercial vendor of energy monitoring equipment. The portal was very useful in monitoring the operation of the HPWH during the project.”

Research Findings About Heat Pump Water Heaters

Part of the value of the system was that it revealed errors in switching or configuration of the heaters. The report showed that data for one unit the resistance element inexplicably came on just after 3:00 am the first day.

The data allowed to researchers to pinpoint the problem: “This led the project team to discover that in addition to changing the temperature setpoint, the units were inadvertently receiving a signal to change the operating mode... This was resolved during the first week of testing.”

Read the published report.

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