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Discussion Starter · #1 ·
My dedicated room has three A/C compressors outside of it. They just outside the front portion of the room, adjacent to the screen wall.


The room is not yet complete.


Obviously, I cannot test the noise situation out now but am wondering if I'll be able to hear them from within my room.


Exterior construction is cedar siding. Inside the room is double drywall and staggered studs. dense insulation. Insulshield. No windows.


I thought of using brick to at as a barrier between the house and compressors. The brick wall would extend up 5 ft (well above the height of the compressors) and extend outward a few feet to act as an enclosure for the units.


Necessary? Any experience / suggestions.


Thanks


Jeff
 

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Jeff:


I have 3 compressors adjacent to the rear part of the left wall in my theater--2 that came with the house (traditional A/C) and 1 that I added for the theater (heat pump). The house is a traditional brick construction with an interior concrete wall that extends up about 5-6' where the compressors hit. We built a 2x6 staggered stud wall adjacent to the concrete wall and stuffed an ungodly amount of insulation in the cavities to mute the compressor noise. Finished wall is 1/2" sheetrock over 5/8" sheetrock, 1" TS+ on the bottom half, 1" 10oz. batting on the top half--standard Dennis design. The compressor lines for all 3 units unfortunately run across the ceiling of the theater--the only one of these that posed a problem was the heat pump line, which forced me to double wrap the whole thing in 1" TS+ and stuff the entire ceiling cavity (about 12" of empty space) with LOTS of insulation.


The 2 existing units are LOUD...so loud that the sound does bleed into the theater when they are on, but it's a very faint sound. The heat pump compressor (or whatever it's called) can't be heard. The 3 compressor lines are silent--I probably spent $500 trying to quiet the heat pump line (the only offensive one, with it's dentist drill whine).


As the noise from the 2 A/C compressors is almost imperceptable even in the silent room (it's even quiter than the G90, which is my sound abatement fixation du jour), I haven't pursued any action yet to further quiet the outside units. My HVAC contractor agreed that a 3 sided "cover" for the noisy units (which would direct the noise away from the house) would *probably* nuke any lingering sound, but this is the same man who thinks I'm carzy for trying to get rid of the heat pump compressor line hum. Plus, he cautioned that it might interfere with proper airflow in/out of the units in question. Plus, my neighborhood covenants (or my neighbor) would likely interject themselves.


To sum up, I don't think that applying noise abatement *inside* the house/room will work if you have loud compressors, unless you plan to have concrete walls 12" thick--opting for either quieter compressors or an external baffle seems the only route that would work. I'm just not sure what an extra layer of brick (the baffle) would bring to the table, though. My HVAC guy could offer no dB estimates.
 

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Discussion Starter · #3 ·
Alex,


Thanks for the response.


THe three lines run in between the staggered studs along the side wall for a bout 15 ft. I will wrap these with insulation but the HVAC guy says these lines are quiet.


So do feel the brick wall option is needed.


Jeff
 

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Discussion Starter · #4 ·
Actually, my HVAC guy just called me and I posed the question to him.


He said, " Are you crazy"?


I probably am.......


Jeff
 

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I think the HVAC Union requires members to insist that HT people are crazy. Just a warning--when an HVAC guy says something is quiet, he means that a *normal* person will think it is quiet...not an HT person. My guy thought I was stark raving mad to wrap/insulate the compressor tube runs--despite the fact that not doing so left a distinct high pitched whine *easily* audible even to non-HT believers. I am *very* glad I wrapped them before we rocked the room--I would have been furious having to live with that noise.


I definitely think the brick wall baffle will help--let me know how it turns out!
 

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when we were building our house, they kinked the ac compressor lines in my media room wall... they sounded like they were whining or gurgling. They didn't want to fix them but I complained enough and they did.


Anyway, the heatpump line shouldn't be making any noise... our's isn't (regular ac, not heatpump tho).


I can hear the AC units outside if I listen carefully, but we have no treatments in the room...
 

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The best ways to stop noise (from the outside) are to first stop the noise at the source and second stop it from entering at the first barrier. There are some very quiet compressor/fan systems on the market. That means a replacement. In the meanwhile, have the units mounted on rubber isolation blocks. This will help some. Brick wall...good idea and expensive. I'd bet new low noise compressors would be less expensive.
 

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".... In the meanwhile, have the units mounted on rubber isolation blocks. .."


I'll ditto this..
 

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Discussion Starter · #9 ·
Good to know.


My HVAC seems pretty knowledgeabe and insist that the lines themselves (which run between the studs for ~15 ft will be silent.


Anyone differ in that opinion?


Thanks


JEff
 

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The quietest compressors on the market at this time are the American Standard and Trane units. I've also had first hand experience with this so now know that yes it is true. They are the quietest and oh did I mention that American Standard is also #1 on the Market and I do not believe that they paid off consumer reports to list them as number one. Geez bland ..........ya know you worry way too much. : )
 

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Discussion Starter · #11 ·
I know my HVAC guy thinks I'm nuts................(probably am).
 

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I'll take the counterpoint position on the compressor lines--but only for ones linking a *heat pump* to an air handler, and only in certain cases. I'm not even sure calling them compressor lines is right, but I can tell you with 100% certainty that combining certain types of heat pumps (e.g., Carrier), frosty weather and home theaters yields a *horrible* whine in the lines. Something about heat pumps going into auto-defrost mode is the culprit--while my unit was defrosting, it whined like a baby for about 8 hours. Absolutely painful noise.
 

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Discussion Starter · #13 ·
Fortunately, no heat pumps for me.


JEff
 

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Thebland,


I'm an HVAC Guy and a HT guy and I don't think your nuts! I would look for a new HVAC company. The only way to keep your customer happy is to help him with his/her needs, no matter how difficult or crazy those reqirements may be!


As for building a wall around the Condensing units... make sure you allow for adequate clearance between the wall and the condensors for proper air flow(16" min). If you are planning on building over the top of the units you will need to maintain at least six feet of clearance from the top of the condensors. The reason for this is to prevent the discharge air (hot) from being drawn back into the condensors, which will cause the equipment to run much hotter and severly shorten the life of your A/C and it will also force the compressor to work much harder and therefore increase your utility bill.


If you are considering upgrading your A/C I recommend that you look at Rheem equipment. All Rheem condensing units use Scroll compressors that are much quiter than conventional reciprocating compressors. I've even installed these outside of customers bedrooms. Take a look at WWW.RHEEMac/scrollinside.com for more info about the compressor.


Yes refrigeration lines can and do make noise! Adding insulation will not hurt anything.


Hope this helps
 
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