Okay, let’s tackle this. So Andrew Diem has 49 years of experience as an architect, which is extremely rare. His education from Harvard University adds significant prestige. Skills like architectural design, sustainable design, and construction are in demand. Location is Washington, D.C., which is a hub for architecture and design. Considering his level of experience, education, and skills, I would estimate his hourly rate to be around $250, which is on the higher end for an architect with his experience and credentials.