Replacing ductwork
Hey all,
Previous homeowner was a big DIY fan. We don't use our furnace/AC very often but need to start improvements for a nursery. Some of the current ducts have right angles and slumps, so there's a couple rooms that get weak conditioning.
My current thought is to replace the flexible ducts with rigid metal. The biggest problem room is a 6" leaving the furnace connecting to a 6" register, running approximately 15'. I believe a rigid duct will make it easier to navigate some of the joists and other pipes in my crawlspace while avoiding slumps. Is there any reason I cannot swap out the flexible duct for a rigid duct?
Additionally, there's a 4" output that just goes...nowhere. It just dumps air into the crawlspace. Is there any danger in putting a metal cap at the main unit and closing that off?
Any confirmation or changes you would advise would be appreciated, as well as any "Oh, you always need more ______ than you think" to minimize hardware store trips.