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heat pump duct sizing

  1. Resize Flex Trunk Duct?

    I am going from a 2 ton Lennox Heat Pump to a 2.5 ton Trane XL15i with variable speed air handler. Currently I have 2 zones. The round flex main trunk is 12" with a 10" going to the second zone. The second zone is for a 320 sq ft bonus room. The first zone handles about 800 sq ft. Do I need to...