The reuse of old structures provides a way to both honor the past and transform old spaces into new uses of the future. We will explore the transformation of sometimes historic buildings into energy efficient housing. We will show how reusing buildings can both reduce material usage, maintain historic character, while also increasing efficiency and comfort. Taking the perspective of energy consultant and rater, we will use examples of historic school rehabs, the transformation of vacant malls such as the old Sears in Rochester,, NY and old factories and office buildings and how they have gone about achieving efficiency and comfort while reusing spaces in a unique way.