As a member of the E Source Technology Assessment team, I’m always actively searching for the newest, coolest, and most promising technologies in the market. Since my team and I first came across rooftop unit (RTU) retrofit controls back in 2011, we’ve been telling our utility members that these devices seem like a great emerging end-use technology. Five years ago, only a small handful of utility programs were beginning to evaluate the technology, and most had never heard of it. Today, we’re seeing myriad new field-test results and encouraging product and market developments that are reinforcing our positive support for the technology as a viable option for inclusion in demand-side management (DSM) programs to deliver energy savings and demand reduction for utility business customers.

A number of utility commercial DSM program and product managers we’ve talked to have told us that increased energy-saving goals have created a greater need to find more and better market-ready technologies for their programs. RTU retrofit controls could fit the bill. After deeply researching the technology, the E Source tech team believes these devices are ready for full deployment in utility DSM programs for commercial HVAC equipment. We provide the details of our technology assessment in our new report Rooftop Unit Retrofit Controls Mature (available to E Source Technology Assessment Service members).

A number of leading utilities have evaluated these retrofit controls devices, and some have even started including them in their commercial HVAC programs. When we began our evaluation of the technology five years ago, only a few utilities had heard of it, as we described for Technology Assessment Service members in our first report on the devices—A Dramatic Boost for Existing RTUs. Since that time, over a dozen detailed evaluations—including field, laboratory, and simulated performance tests—have been conducted and their test results have been reported publicly. What these evaluations have consistently shown is that, for the average RTU retrofit installation, the technology saves energy and reduces peak demand associated with RTU operation, with average savings typically on the order of 30 to 40 percent for both.

Field tests demonstrate significant energy savings

We’re aware of over a dozen field demonstrations where rooftop unit retrofit controllers have been evaluated since 2012. The consistent positive test results indicate that these devices could be considered good candidates for inclusion in utility commercial HVAC incentive programs across the US. However, careful consideration should be given to climatic and seasonal effects on overall savings potential.
Field tests consistently demonstrate significant energy savings

One particularly exciting development in the RTU retrofit controls market is that Internet connectivity is now making possible convenient user interfaces for monitoring and controlling RTU equipment, including features that provide non-energy benefits that are often more attractive to customers than energy or demand savings. For example, for some of these products it is now possible to remotely monitor and adjust RTU operation according to predictions of indoor climate conditions and occupant comfort levels. This same wireless connectivity of control devices also enables remote monitoring and tracking of RTU equipment to detect faults and diagnose minor problems so they can be fixed before they cause catastrophic failures.

To learn more, E Source Technology Assessment Service members can read our Rooftop Unit Retrofit Controls Mature report. We also provide a wide range of information on promising new technologies in our Emerging Technology Resource Center, our biannual Tech Roundup webinars, and our annual Top 20 Technologies and Trends reports, also available to Technology Assessment Service subscribers. If you have any additional questions you’d like us to answer, please don’t hesitate to send them our way using the Ask E Source service!

Contributing Authors

Lead Analyst, Technology Assessment

Bryan Jungers conducts research on emerging, energy-efficient, and distributed energy resource technologies. His main areas of expertise lie in...