I am looking for a good book on AHUs. I need to go from hi I am an AHU to here is an air hood and this is how we balance a room. Some of the AHUs in the buildings I have are from the mid 1900s. Some of the buildings were built in 1919. We have a centralized chiller and boiler plant that feeds almost all buildings. Some of the air handlers have hot and cold decks. I have been put in a lead position so I am learning on the fly. Normally I am the boiler expert since I been operating and repairing boilers since I was 19. Now I am running the air handler side of things. If anyone has a suggestion as to where I should go please let me know.