i have a new Goodman 2 stage, 80%, 90k downflow furnace that goes into 8, six inch, in ground clay ducts that flow into 22 registers in6 rooms in a 2100 sq. foot area in a slab ranch house. It seemed noisier than my 37 year old 150k furnace so i asked my installer to turn the blower speed down. Now Im used to the noise and Im thinking Ill ask him to turn the speed back up to factory. Not sure what to do.