I had learned building science while working on my engineering degree which had given me several advantages as a contractor. Home inspectors also learn rudimentary building science, but I had another advantage. I had actually put the pieces together and knew how everything worked together.
Another problem I saw when looking for a home inspector was that most of them gave a big list of all the services they offered but had no guidance on what I would actually need. After digging in to it a little bit I found out I didn't need most of it!