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My duct system is currently in the attic. I’ve decided that by putting in a drop ceiling in the hallway and making use of the fur downs over the kitchen cabinets that I can get them below the normal ceiling level and the insulation. I know how to down size the duct as I go to get the proper back pressure but I need to locate a chart or formula to find out the right size to come off the plenum with. The current duct system uses round duct and has two 14″ runs coming off, however, I’ll need to use rectangular in the new installation,at least to the point I can down size enough to get the round into the space available. With the duct system below the ceiling and insulation, does it still need to be insulated itself? I wouldn’t think it would be necessary since any heat loss would be into the heated space anyway, but I want to be sure. I know that it is recommend in some installations to keep the ducts from sweating when thw AC is running. I also plan to install additional return ducts from a couple of more remote rooms that don’t get adequate circulation. If I run these under the floor, do they need to be wrapped, and if so, how much insulation do they need? Thanks,Kris G.
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My duct system is currently in the attic. I've decided that by putting in a drop ceiling in the hallway and making use of the fur downs over the kitchen cabinets that I can get them below the normal ceiling level and the insulation. I know how to down size the duct as I go to get the proper back pressure but I need to locate a chart or formula to find out the right size to come off the plenum with. The current duct system uses round duct and has two 14" runs coming off, however, I'll need to use rectangular in the new installation,at least to the point I can down size enough to get the round into the space available. With the duct system below the ceiling and insulation, does it still need to be insulated itself? I wouldn't think it would be necessary since any heat loss would be into the heated space anyway, but I want to be sure. I know that it is recommend in some installations to keep the ducts from sweating when thw AC is running. I also plan to install additional return ducts from a couple of more remote rooms that don't get adequate circulation. If I run these under the floor, do they need to be wrapped, and if so, how much insulation do they need? Thanks,Kris G.