4" or 6" Ducts. Which is better? I just had Central A/C and Heat installed and most of the rooms connected to the end of the Trunk line barely push out any air. There are currently 5 Registers/supply's (Cat Room, Bathroom 1 & 2, Computer Room, Baby Room) connected to the end of the trunk line, all seem to be 6" ducts. The lines in the beginning of the Trunk (my bedroom) pump out an enormous amount of airflow, so much that I leave the vent closed.
my question is, When do i use 4" or 6" ducts? I believe the beginning of the Trunks have 6" and 7" and towards the end are all 6". I need to increase the airflow at the end of the Trunk Line (the 5 registers).
I got two different answers when i went to Home Depot and Lowes. One said I need 6" ducts at the end while the other says to use 4" ducts because the airflow is the weakest and I am just moving cold air.
Do I leave the 6" at the front and change all at the end to 4"?
Is using a 6" to 4" reducer the same or do i have to replace the actual piece at the trunk.
Here is a PPT drawing of my home. Please note that the Trunk/Unit are actually the same but since I have a crawlspace running alongside my home, It was just best to draw it twice. Also, it may look reversed but the 1st page is drawn horizontally and the 2nd vertically. Just picture the crawlspace in your head to line up the direction in your mind.
I am not concerned about the bathrooms, primarily the Computer Room (1st floor), Living Room (1st floor), Main Bedroom (2nd floor) and Baby Room (1st floor).
My beams run in the same direction as the arrows for ductwork. If you need size dimensions, I would my house is roughly 35 feet by 60 feet. 35 feet is the direction of the arrows.
I would prefer to reduce the Main Bedroom and increase flow to the Living Room (directly below Main Bedroom (2nd Floor) and Computer/Baby room (Below Cat Room on 2nd Floor)