Cold air return vents FAQ

Oct 26, 2003 11 Replies

When my furnace is operating ( heat mode ) the blower motor on high, the cold air return vents make a howling noise,( in my bedroom ) due to the suction of the blower motor, pulling the air thru the vent.



Is there a way to defuse the air being returned to( that particular vent ) the furnace, with out reducing the amount of air being returned to the furnace.



The duck work amplifies the noise, and it resonates in the bed room.



Thanks Tom


Your return air ducting, including the RA grille, may not be large enough to meet RA requirements at proper air velocities. I have a little info on duct sizing in page below. Darrell

Have that duck pull the fuse out.

Proper duct sizing helps.

Find the duck, and remove the quacker.

Try removing the grille and see if it goes away. If it does buy another style of grill to fit. Meanwhile think of the noise as birds in the spring!

Sounds like your system doesn't have enough return air ducking. You oughta let a heating guy in and take a quack at it. Somewhere on the web you can find a chick who will fit the bill. But your original ducking isn't all it's quacked up to be.

Might want to try a gaggle search on return air ducking?

If your furnace is running with inadequate return air ducking, the energy bill is probably costing you a waddle of money. It really is goosing you right in the pocket.

Maybe you can find a techie to get over there right quack?

It could be a sign of inadequately-sized ductwork, or at least, a grille that may be too small. But, even if they are sized correctly.........I've had jobs where we have installed Brand X return grilles and find that they 'sing' when air is moving through them. We remove them and replace than with Brand Y, same size, but a slightly different configuration or construction....and the problem goes away.

Wait 10, 20 ,50 yrs. You will be the ASS that experimented, and HD now wont warranty your PUSS,,,,, Wake UP It lasts thousands of years done right ,, Bozo, YOU a BOZO , BOZO

When we had a new furnace installed the same thing happened. The installer just bent the (so they were at less of an angle) louvers of the return grill so more air could get through. No more noise.

Just so you know, (no flaming, just facts) that is a sign of an improper manual D, and you have an undersized return, if only by a few square inches. A properly sized return you should almost hear nothing.....just finished one that has 3 in the home and you actually can not tell if the units running or not.

>

  1. What is a manual D?
  2. With the grill removed there was no noise.

Duct sizing calculation.

Grill adds resistance and is figured in a manual D calculation so you dont have noise when its on. Velocitys are too high if that is the case.

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