Hello, I recently replaced my furnace/ac with a Trane 3.5 ton unit and there
is some return air flow noise, I think from air velocity, that I would like to lessen.
I believe everything is sized OK -
1 - 3.5 ton unit (about 1575 cfm ?)
2 - left/right supply branches 20x8 (about 1700 cfm (855x2)?)
3 - one main return trunk serving two floors 24x12 (about 1450 cfm? )
4 - Filter 16x25 (pleated - cheap)
5 - Blower on medium
6 - Cools both floors ok
My questions are -
- how large should the opening behind the two return air grills be? The grills themselves are 22x22, but the cutout is only 12x12.
- is lining the duct worthwhile?
- is there better sound absorbing grills
- other solutions ???
Thanks in advance - G