Engineering students benefit from an active and interactive classroom environment where they can be guided through the problem solving process. Typically faculty members spend class time presenting the technical content required to solve problems, leaving students to apply this knowledge and problem solve on their own at home. There has recently been a surge of the flipped, or inverted, classroom where the technical content is delivered via online videos before class. Students then come to class prepared to actively apply this knowledge to solve problems or do other activities. In this paper, recommendations are made for applying this educational technique to large engineering classrooms. These recommendations are based both on a literature review of flipped classes and the evaluation of a case study of a large Introduction to Environmental Engineering class. The case study evolved from a traditional lecture-based classroom through two different versions of a flipped classroom. Evaluation of students' interaction, preferences and performance are used to make recommendations about the video time, use of class time, course organization and student assessment.