Here, hopper-style windows are used as transoms to provide ventilation without compromising security. Before ordering windows, think about how you will install the transom above the door. Will there be a space in between, trimmed out as in this picture? If you plan to mull the transom window directly to the top of the door, make sure your salesperson knows and provides a factory trim to cover this joint. Or better yet, have the factory mull the door and transom together. This connection can be a tricky one to make on the job.