We are replacing the hvac in the house (well we are getting a hvac comany to do it) and we are going to redo the ducting as there are some serious shennanigans in the attic and it needs to be re-done. I want new ducting to go with the new equipment as opposed to the redneck stuff that is up there right now.
We are going with foam board for the main trunk lines and with supported flex duct to the registers. (meaning the flex duct will be on a flat surface and not willy nilly over joists etc.) I have the correct sizes for the ducting to be installed. my question is if you have a 5 inch duct or a 6 inch duct do they all terminate in a standard size register or are there different size registers for the different size ducts. I have looked around but have not seen an answer to this question. We actually have sizes ranging from 5 inch to 8 inch depending on the room. The hvac has run the manual J and used the ducolator to ensure that we are installing the correct sizes for the rooms so no issues there.