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Hello everyone,


Looking for some help on modifying my existing system to put some air movement in my basement.

Currently have a 3 ton ac/ furnace system in the basement. I believe i have standard 9inch tall return duct? Then then two 3 inch tall rectangle duct runs in the shape of an H with the central unit in the center of the H. One long side of the H has the duct length of about 60ft the full lenth of the house. The other shorter leg of the H duct run is about 40ft run.

How can i load balance these two trunk duct runs? The longer run always is hotter and blows stronger than the other side of the house on the shorter H leg.

Second part is can this system handle adding in say 2-3 vents off the trunk runs to blow into the basement?
 

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you would have to measure the actual size of the ducts, there is no standard anything. the unit is 3 tons is vague, thats just a ballpark of 1200 cfm rating. could be much higher or lower depending on fan speed and static pressure of the ducts. If the longer run has better velocity and heating than the short run something more is in play. there may be dampeners on the branches or takeoffs adjusting air flow. People often think ductwork is simple and any moron can do it. Having it done right and even flows is an art
 
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