Jeff Tiller, PE, is a professor in the Building Science program at Appalachian State University where he has taught construction-related courses for over 20 years. He is a registered professional engineer in North Carolina and has been highly involved in dozens of high efficiency buildings. He has written numerous articles and given hundreds of presentations to audiences of builders, contractors, and design professionals on energy codes, high performance and sustainable buildings, efficient HVAC systems, solving moisture and indoor air quality problems, and incorporating renewable energy systems into buildings. He has written the “Builders Guide to Energy Efficiency Homes for North Carolina” as well as for several other states. Most recently, his Appalachian State student team was one of five grand finalists in the Department of Energy-sponsored Race-to-Zero residential design competition held in Denver, Colorado. There were a total of 33 university teams in the competition from the United States and Canada.