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Thread: Advice on replacing 20-year-old AC with something quieter?

  1. #1
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    Advice on replacing 20-year-old AC with something quieter?

    I have 20-year old central AC system that needs replacement. It uses old-style refrigerant AND the neighbor complains about the noise. I'm hoping someone here can make a recommendation.

    Here are a few facts about the current setup. The outside unit is a 2001 Trane Xe1100 (2.5 tons, I believe) located in the roughly 20-foot gap between my house and the neighbor's. It's coupled to a somewhat newer Trane XV95 gas furnace in the basement. The house is an old 2-story + unfinished basement stucco place that's about 1650 square feet. Climate is moderate NW interior valley. Summers generally have 3-4 weeks of 90 deg. temperatures but 80s are much more common highs.

    I'd like to find a quieter replacement for the current AC. When I stand 5 feet from the outdoor unit the noise measures about 66-69 decibels. From my reading it's not clear to me whether newer Trane ACs will be significantly quieter, since the numbers reported seem to vary from roughly 56-69 and I can't guess how much I might actually benefit from the lower reported number. Any wisdom on this?

    A ductless mini-split seems likely to be much quieter but I wonder how much grief I'd run into if contractors try to string coolant hoses inside the walls of this 90-year-old house and attach multiple indoor blowers to the lath and plaster walls.

    I'd appreciate any insight you can offer about my best bet here. Thank you.

  2. #2
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    Side discharge inverters are quiet and typically have a smaller footprint than standard vertical exhaust models. Even vertical conventional inverters models are quiet. Did you try to put a compressor sound blanket on your existing unit to help quiet it a tad? They can be mounted practically next to a wall. Thinking your replacing everything? If so get a AHRI matched system. Depending on SEER and furnace efficiency there are rebates and the Federal Tax Credits.

    May want to do a load calculation to see what you really need especially if you tightened up your residence over the years.

    Here’s a free one

    https://www.google.com/url?sa=t&rct=...wxqi0c65CNPb1r

    Register your system of choice as manufacturers warranty decreases if system never gets registered.

    Ask for a start up/commissioning report on your system
    , things like static pressures, final field refrigerant charge, amprege draws of motors and compressor, temperature rise across HX, CFM set, etc.etc. are within manufacturers specifications.

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  4. #3
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    56 Db 66 Db are low #'s!

    Your not going to get much lower!

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  6. #4
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    Thread Starter
    Thanks very much for the tips, Joe.

    In answer to your questions:

    I had not looked into a sound blanket but will investigate.

    Rather than replace the whole system, I'm hoping just to re-do the AC portion if I can--the furnace is newer, in good shape, and pretty efficient.

    I'll definitely do a load calculation.

    Thanks again.

  7. #5
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    Thread Starter
    Thanks for the info, pecmsg. My current system runs at a pretty constant 66-69 db, so if I could drop it to a constant 56 db that would be a win. But my reading of the specs on new systems suggest that the lower 56 db figure is a transitory minimum rather than a steady-state figure. In other words, it appears that they run just as loud as my current setup during some unspecified portion of the time they're on. If it happens for long enough durations then I will have spent money for no real improvement in the noise situation. I'll just end up with less money and a neighbor who's still unhappy. Nothing to look forward to there!

  8. #6
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    The old Tranes were very noisy due to the Climatuff recip compressor. Those were TANKS but noisy tanks. You have to spend the bucks to get these super quiet units. Even 71 db, which is the entire 14 SEER Trane line is much quieter than what you have.

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  10. #7
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    Quote Originally Posted by NeedSomeQuiet View Post
    I have 20-year old central AC system that needs replacement.
    It uses old-style refrigerant AND the neighbor complains about the noise.

    I'm hoping someone here can make a recommendation.

    Here are a few facts about the current setup. The outside unit is a 2001 Trane Xe1100 (2.5 tons, I believe) located in the roughly 20-foot gap between my house and the neighbor's. It's coupled to a somewhat newer Trane XV95 gas furnace in the basement. The house is an old 2-story + unfinished basement stucco place that's about 1650 square feet. Climate is moderate NW interior valley. Summers generally have 3-4 weeks of 90 deg. temperatures but 80s are much more common highs.

    I'd like to find a quieter replacement for the current AC.

    When I stand 5 feet from the outdoor unit the noise measures about 66-69 decibels.

    From my reading it's not clear to me whether newer Trane ACs will be significantly quieter,
    since the numbers reported seem to vary from roughly 56-69 and
    I can't guess how much I might actually benefit from the lower reported number.

    Any wisdom on this?

    I'd appreciate any insight you can offer about my best bet here. Thank you.
    Sound Limits / NOISE CRITERIA

    What is the Current dbA reading at your property boundary?

    What dbA reading do you wish to achieve at your property boundary?

    _______ WHAT Sound Limit is mandated by a City or County ordinance?
    ______ 60 to 65 dbA - Daytime _____ ?
    ______ 55 to 60 dbA - Night ____ ?


    __ 22 TYPICAL CITIES
    https://kineticsnoise.com/industrial...httime%20hours.
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  11. #8
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    Thread Starter
    Dan--

    The current measurement I posted (66-69 decibels) is at my property line. I'd like to get closer to 55db. That would put me within the legal limit where I live and (more important) give my neighbor some relief. I suppose few db above that would probably be ok in that it would still be a relief for the poor guy.

  12. #9
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    PORTLAND OREGON

    https://noisefree.org/wp-content/upl...and-oregon.pdf
    Attached Images Attached Images  
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  13. #10
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    Quote Originally Posted by NeedSomeQuiet View Post
    Dan--

    The current measurement I posted (66-69 decibels) is at my property line. I'd like to get closer to 55db. That would put me within the legal limit where I live and (more important) give my neighbor some relief. I suppose few db above that would probably be ok in that it would still be a relief for the poor guy.
    What is easily achievable with a modern condensing unit?

    TRANE Series XR17 ___ 4TTR7036
    __ Installed May, 2016

    2" from frame _ _ 67 dbA Average
    10 feet from unit __ 54 dbA Average

    What is the current dbA reading within 4" of the condensing unit frame?
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  14. #11
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    BRYANT model 124ANS
    __________ Sound Rating 71

    ___________________ https://www.shareddocs.com/hvac/docs...S124ANS-06.pdf

    .. Page 8 ... __ 53.5 dbA 10 feet from Unit
    Attached Images Attached Images  
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  15. #12
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    Thread Starter
    Dan,

    Thanks for the additional info.

    In answer to your question about current dbA within 4" of the condensing unit frame, the answer is about 72 (allowing for occasional fluctuations). Five feet away at the property line the number probably averages around 67dba over time. The sound doesn't attenuate with distance as much as the standard formula would predict and I believe this is because of reflection. My neighbor's house and mine are no more than 12 feet apart with a flimsy cedar fence between so the sound bounces back forth against hard stucco surfaces on each house.

    The more I investigate this the more I'm coming to believe that I need a quieter, more modern setup AND I need to move the condensing unit around to the back patio. Although I'd rather not have it in a sunny south-facing location like my patio the movement would eliminate the sound reflection problem as well as getting a few feet further from the property line. Then I'd have a little more leeway. Unless I'm mistaken, the helpful specs you provided tell me that I need at least 8 feet distance from property line to achieve a 55dba level there even with the more up-to-date equipment.

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