Dr. Lieko Earle

Dr. Lieko Earle is a senior researcher in the Building Technologies and Science Center. Her current research centers around innovations that enable buildings to be grid-interactive, including home energy management systems (HEMS), connected/smart appliances, and electrification strategies. She is particularly interested in challenges and opportunities around how to retrofit existing buildings. She has worked at NREL for 11 years and has led the Residential Group’s field testing program for most of that time.  She holds a BS in Physics from Brown University and a PhD in Physics from the University of Colorado. 


Bethany Sparn

Bethany Sparn joined NREL in 2010. Her research focuses on connected building loads, residential HVAC equipment, heat pump water heaters, automated home energy management devices, and whole-house performance field testing. She supported the design and build-out of the Systems Performance Laboratory in the Energy Systems Integration Facility, which provides a test bed for evaluating home energy management systems, demand response strategies, distributed energy resources, smart appliances, and other innovative sensors and controllers. She has a BS in Physics and Mathematics from the University of Puget Sound, BS in Mechanical Engineering from Columbia University, and an MS in Mechanical Engineering from Colorado State University. 


Dr. Xin Jin

Dr. Xin Jin joined NREL in 2014 and is currently a senior researcher in the Building Technologies & Sciences Center. He is also the Sensors & Controls innovation area lead for NREL’s Buildings Research program. His research focuses on building-grid integration, smart home and smart community, building controls, and machine learning & AI applications in building systems. He has authored more than 50 peer reviewed technical publications and is the recipient of a U.S. patent and the 2018 R&D 100 Award. Xin holds a BS in Mechanical Engineering from Shanghai Jiao Tong University, and an MS in Electrical Engineering, an MS in Mechanical Engineering, and a PhD in Mechanical Engineering from Pennsylvania State University. 

Dianna Cacko

Dianna Cacko is a Field Outreach Manager at Slipstream and focuses on the implementation of residential HVAC rebate programs for Michigan’s rural electric cooperatives. The integration of heat pumps into existing homes across Michigan to reduce electric resistance and propane based heating sources is her primary focus. Dianna has been involved in the implementation of energy optimization programs in Michigan since 2011, and has been working with contractors to increase awareness of cold climate heat pumps and the benefits they can provide homeowners and contractors since 2016.  Over the last few years she has been an active contributor to Slipstream studies monitoring market installed dual fuel central air source heat pumps and heat pump water heaters in the State of Michigan. 

Greg Nahn

Greg Nahn is a Senior Building Science Specialist and has spent the past two plus decades working to advance the design and delivery of effective residential energy efficiency and building retrofit programs. He is a proven visionary, trainer and communicator with extensive background in supporting energy professionals and the identification and promotion of energy efficient technologies and retrofit strategies for both existing and new residential construction. Greg is passionate about increasing energy efficiency in the residential housing through the re-development of buildings with emerging technologies and proven solutions to meet the challenges and opportunities of a clean energy transition.