Longer duct runs to lessen noise in small condo?

[caslon]

My condo is 887 sq. ft with the furnace/evaporator in a small hall closet with the air return below it (by design).

2 Ton Carrier 38HDR and Carrier Performance 80 furnace. The 2 bedroom 1
bath has only 5 registers and the return (which is plenty big).

I know the circumstances with having a small condo and everything in a small hallway closet. Howerver, I just feel there is more I can do to lessen the
noise coming thru the duct work. The duct work is flex insulated, but the
thing is...there's such a short run from the plenum to each of the 5 registers.

This causes a louder noise than I would like. Not extremely bad, but somewhat like the distant sound of the ocean roaring coming thru the ducts.
I've done about as much sound absorbing at the large cavity return under the furnace. The company tech is coming out tomorrow afternoon to look at it.

I'll have him check the CFM because when I stand 8 ft. back from the large living room register up near the ceiling...it actually blows my hair back, and moves my vertical blinds quite a bit.
It cools the unit well, and everything is working fine.

I'm mulling over maybe having the duct lengths extended and using flex
insulated acoutical ducting, the kind with perforations inside. I'm thinking
extending the duct runs might help with the ocean sound. Thoughts?

I realize the limiting factor of having HVAC in a small condo hall closet, but I'm determined to at least attempt some quieting.

Any help appreciated before he arrives tomorrow afternoon. Thanks guys.

[beenthere]

The noise is most likely more from the ducts being undersized, then just because they are short.

[Sharp Snips]

I'm mulling over maybe having the duct lengths extended and using flex
insulated acoutical ducting, the kind with perforations inside. I'm thinking
extending the duct runs might help with the ocean sound. Thoughts?


Attenuating flex duct is certainly an option. The longer the length the better the chances you will have at squelching your ocean sound. From what I read though, room to extend your attenuating ducting may be the real issue. Good luck.

[fenian]

have him check your static pressure before messing with duct.

[caslon]

The noise is most likely more from the ducts being undersized, then just because they are short.

Thanks for the reply. I have a digital camera and it's no sweat to get up in the attic and snap some pics. I hope you'll reply afterwards.

[dash]

Thanks for the reply. I have a digital camera and it's no sweat to get up in the attic and snap some pics. I hope you'll reply afterwards.

Include the return and the grilles!

[eetechster]

if you post your duct size and length and register size and typ it may help. some one may be able to help you determin if your duct work is properly sized and maybe equipment is correct. It does sound like under sized duct but mor info is needed to make a proper diagnoses of your system, your contractor shuld be able to help you with that, without being there its hard to tell without a lot of info???.... I wish you the best of luck.

[caslon]

Coming up with pics in a few momemts...attics. ducts.

Hang on.

[captube]

Coming up with pics in a few momemts...attics. ducts.

Hang on.

I'm staying up :cool:

[caslon]

Here are the pics requested. There's one large duct not seen in the pic behind the plenum. It's beefy big and goes to my living room vent. Immediately near the plenum! That may be the one to concentrate on quieting.
The big one at attic access goes to my bedroom to the right and to ajoining bathroom.

Actually guys...I spend most of my AC time in my living/dining room area. That's
where I would like the noise decreased. I don't really care about the noise in my bedroom, which by the way, has a large vent as it is the same floor plan as my living room. My 2nd bedroom/ office? Again not a major concern.

I squeezed the plastic insulation wrap, and even tho they look big and beefy, the acutal diameter of the duct seemed not that large, but I could be very wrong.

Southern California, relatively mild temps.

http://home.san.rr.com/jdc/duct1.jpg
http://home.san.rr.com/jdc/duct2.jpg
http://home.san.rr.com/jdc/vent1.jpg
http://home.san.rr.com/jdc/vent4.jpg

[beenthere]

A combination of undersized ducts, and undersized supply grilles.

Thats a guess, I can't tell what the size of the ducts are from the picks.

[caslon]

A combination of undersized ducts, and undersized supply grilles.

Thats a guess, I can't tell what the size of the ducts are from the picks.

Ya, I know...it was like squeezing Charmin tissue paper as they were so well thickly wrapped.

The vents sizes? 3- 12"x6" for the smaller rooms... 2 that are 16"x8". One in the living room, one in the bedroom which has the same floor play layout as my living room.

I agree with you about the lack of attic space to extend ALL ductwork, but I would at least like to concentrate on the sound of the living room vent and the small size of the dining room/kitchen vent.
That one smaller vent has to serve both my kitchen and moderately small sized dining room.

I'm not at all unhappy at having purchased the 2 ton Carrier 38HDR. My condo unit is located above 2 garages (quiet garages). My little condo retains heat. I believe 2 ton was the right choice. I am somewhat dismayed that I can sit at my pc 2 feet a window and outside is a quiet running Carrier 38HDR. Inside is a somewhat mild ocean roar from everything else about my AC.

Another thing...it'll take about 10 minutes for that Carrier Performance 80 series to heat up my condo in winter. When it gets chilly, I'll get up from my couch and gladly fire it up again.
Why to I have to deal with 2 small jet engines taking off, to heat up a small condo?

Can that Carrier Performance 80 series furnace be somehow set to just start and stay with the
slower second stage upon fire up?

Buying heating and cooling for 2 bedroom condos these days is such bull****, I can' believe it.

[beenthere]

Its pretty easy to increase the size of the ducts. The kitchen supply can be increased easily also.
The wall supply is another story.

Might be just as easy to add another supply to the living room, and to the bedroom.

[caslon]

Thanks for the reply. Also, I'll be reasonable when the company tech comes out to try and help me.

I'm a contractor myself, and I don't plan on letting him explain away my problem with technical lingo. If he has professional options to offer, I will consider them.

Otherwise, I'll just find another HVAC contractor who will at least try and deal straight with me, (me not knowing as much as you guys).

BTW..the living room is a slanted ceiling with no crawl space. No place to even step to put another vent anywhere there, unless I want twins. That's OK. I was even thinking of putting a small vent in the hallway. Maybe not, lol. There's crawl space access over at my dining room. Wow, that might actually be a good idea. It would take the load of that little vent that serves both my kitchen and dining room.

First things first. I will let you know what he addresses when he shows up.

[beenthere]

Nothing wrong with 2 supplies side by side. With possible exception of looks.

[caslon]

Ya, I suppose, lol. I'm getting us off track.

Question...if I want to just concentrate on reducing the sound of that big vent in my living room...it is possible I could reduce the sound of the ocean by
utilizng what little attic space I have and run a longer duct to that living room vent?

Noone actually addressed this possible remedy. I'd be willing to order insulated acoustical larger (if deemed advisable) ducting.

It's not that huge a deal, but I kinda have set a challenge to at least try and reduce the db's to a gentler sounding ocean waves breaking on the beach, lol.

I bet most here deal with bigger dwellings where my concerns don't come up very often.
So have tolerance and sympathy...empathy if you have that too.

I totally dig my Carrier slimline 38HDR. Damn...I am sitting 2 feet from it and cannot hear it thru a large single pane sliding glass window. I never considered the noise coming from the
inside unit.

[beenthere]

Increasing its length should reduce sound some. How much is a guess.
But, as you increase that ducts length, you decrease the amount of air that room gets. And increase all the other rooms. possibly making youor bedroom louder.

[caslon]

That's OK Beenthere. I am not those that need an AC to sleep at night.
My bedroom ceiling fan on high speed cooled my sweat down so well, even
when it was really hot hot. Maybe in the morning, I would like it to kick on while I awake.

The thing is BeenThere, that large duct from the plenum is about next to nothing from there to my living room vent. Transferring all the noise.

Again, my main noise concern is not my bedroom, nor my bathroom or second small bedroom/office.
It's where I spend most of my "AC" time I care about reducing noise. The living room and dining room.

Also...as undetermined as the one duct leading to my living room is (not shown in pics), it's probably not undersized. It's as big as the ones that feed the smaller vents, that's pretty good sized, it appears to me.

I think the issue here is the close proximity of that large adequate duct that feeds my living room from the plenum, thus easily transferring sound. Like less than 2 feet, heh.

[beenthere]

That is because the grille is too small.

[caslon]

Than again...my living room isn't an office building, nor do I want vents resembling that.

I know this is rarely an answer to a noise problem, but can the tech come in and slow down the blower motor just for the AC?

Did it phase any here that I could stand back 8' from the register and feel my hair blowing in the wind?

I've tried to minimize the blower fan noise coming from a large return duct HVAC closet.
I lessend that...to a degree.

I posted pics of my attic. Including the main noise I am bugged with. The seemingly well sized and very very short duct from the plenum to the living room.

Run that ONE duct longer (if I can, to reduce noise where I "AC" most, my living room) or what?

Can I get some views on that possibility? I've reply posted at least 15 times to help you help me.

[beenthere]

Did it phase any here that I could stand back 8' from the register and feel my hair blowing in the wind?

That is an indication of undersized ducts, or registers/grilles.

i dooubt your moving 800 CFM so as it is. Slowing the blower down, could cause the coil to freeze.

The tech will have to check current CFM.

[caslon]

That is an indication of undersized ducts, or registers/grilles.

i dooubt your moving 800 CFM so as it is. Slowing the blower down, could cause the coil to freeze.

The tech will have to check current CFM.

As little as I know about HVAC..that is what I was concerned about too.

I don't believe my 2 Ton Carrier 38HDR is oversized for my 887 sq ft. condo.

I have a garage below both my living room and my bedroom. Take a guess as to where all that heat goes. As it is, even that 2 ton Carrier takes awhile to cool down my place.
An 8'x6' living room window that, while not in the sun too long....still transmits ambient heat.
To give you an idea...at midnight when it's cooling down to 69F outside, even with fans..it was 80F inside before AC. I do NOT regret getting that 2 ton quiet Carrier 38HDR condenser.
The Carrier 38HDR works like a champ so far. Cycles on just when it's supposed to, not excessively.

The airflow seems somewhat excessive out my living room large vent, along with the noise.
Mostly it's the noise. That waves breaking on the beach noise, lol.
Maybe that comes with an 887 sq. ft. condo with the whole unit in the hallway closet.

It's kinda simple. A small condo. Plenum connects to ducts that aren't longer than 12 ft. at the most. Noise is bound to be transmitted.

I was asking how/what I can do to minimize that transfer of sound from the blower motor/whatever on such a short run of duct work.

Move? Not untill the housing market improves.

Also, it's interesting that some acoustic techs (not AC techs) have a decible meter in their kit.

Not a bad idea.

Just one other thing. Flexible insulated acoustical ducting for AC. Not a peep about it here.
Not that it applies to my situation. Tiny perforations on the interior of a flex insulated duct.
It's supposed to do well absorbing sound from the blower motor and other sounds transmitted thru an AC duct.

[beenthere]

Accustical duct is resrtictive.

Again, the noise is from undersizing the ducts and grilles.