There is loud noise coming from air return (12x12"). This one is at the ceiling in family room on first floor. So they cut another hole (same size) in laundry room which is behind family room to open another return using the same duct. There are still noises from both returns but better in family room and louder in laundry room. My concern is that is it OK to have air return in laundry room? Another contractor suggested connecting new duct from unit and create new air return in hallway instead and close those two completely. Is that possible? What caused the noise and what are solutions?

I also noticed that after they added return in laundry room, air conditioning doesn't work well upstairs at all. Do you think adding the return in laundry room caused this? There's another bigger return upstairs. That one is quiet.This is new home we are buying? Please help!

The return duct needs to be where air from the supply freely circulates through the cooled area to it. Behind a closed door to the laundry room wouldn't work as well. For the hallway, depends on the layout.

I am not sure what causes the noise. The duct could be transmitting vibration of the blower. A 12'' x 12'' inlet should be big enough to avoid whistling from too high of air velocity. The duct could be loose and vibrating.

As the buyer, you have leverage on getting this fixed.

If they can't fix it, post back with a description of the noise, type of ducts, and anything else you feel may help.

Oh, besides the closed door problem, it may be cheaper to leave the heat and moisture in the laundry room rather than pull it into the system.

Thank you so much for reply. As you said, I also didn't like the idea adding one in laundry room. I read in the manual which states clearly not to have air return in kitchen, bathroom and laundry. They did it because the laundry room is in between family room and garage where the unit is. It is easy for them just to open another grill from the same duct I think. Now we have to leave the laundry room door all the time which is not right. And when we use the laundry, It wouldn't be healthy, would it, to have the bleach, heat , moisture going back into air return.

The noise is like the furnace noise in garage that travels through the duct to air return. It's like constant wind noise.

It sounds to me like the ducts are undersized, or the blower speed is set too high.