# Remodel



## Johnny dee (3 mo ago)

We have relocated the hvac system in the basement about 10 ft away. Adding a few branches and some returns. Our installer decided on a 20 × 20 90 deg elbow with 2in throat as the plenum, right off the coil. Him having no knowledge of duct sizing and calculations. And not performing any air measurements, or anything. My question is , will this work? What size do I start reducing this at? Only a 3 ton a.c. 96% new 2 stage furnace, with only 1200 cfm, is it salvageable?


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## bobber (Jun 24, 2021)

While it's done by people with no knowledge of ductwork all the time, it's far and away the wrong way to do it. If he doesn't know ductwork, then how can he properly size any changes? Have someone evaluate and size the changes and get it done right.


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