The Energy Department's Challenge Home program certifies homes that are 40% to 50% more energy efficient than typical homes. It also helps to minimize the risk of indoor air quality problems and ensures compatibility with renewable energy systems. Through the Challenge Home program and its original Builders Challenge specifications, the Department has certified more than 13,500 homes, which are saving consumers more than $10 million each year. Among these certified homes, more than 1,350 are considered zero net-energy ready homes based on Home Energy Rating System (HERS) scores of 55 or lower. PHIUS certifies building designs that are 65% to 75% more energy efficient than a typical new home, even before installing renewable energy systems. PHIUS has also trained nearly 400 construction professionals to build these homes. See the Energy Department Progress Alert