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  1. #40
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    Quote Originally Posted by Mike530 View Post
    Thanks thermojohn. That explains the noise issue pretty well.
    In regards to lining the return cavity to reduce sound....can you also build a metal can or box? That is what my contractor wants to do, but I preferred they line it with duct board for noise reduction purposes.
    For deadening sound, duct board will absorb the sound associated with the blower pretty well. There are even a few tricks we do with duct board to attenuate it even more... But that is an ancient Chinese Secret we only offer for our clients.

    Sheet metal alone does nothing to attenuate blower noise.

  2. #41
    Join Date
    Jul 2008
    Location
    Rochester NY
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    4,721
    Quote Originally Posted by energy_rater_La View Post
    Ted.stop.

    the OP's questions are for gas furnaces. read the thread.
    LOL, No, I think they want a comfortable house. A gas furnace is their assumption of the best way to achieve that. I also think the OP came looking for professional advice.

    A salesperson suggests what they think you are likely to buy. That is their design orientation. "This person wants a gas furnace so that's what I'm gonna sell 'em."

    A consultant attempts to understand the client's problems and brings their expertise to bear. They attempt to put themselves in the client's shoes and think "what would I do if this were me?" Even if it means extra effort and time.

    I save my client's 30-70% on their energy costs, and they rave about comfort improvements. I do not do this by selling people what they "think" they want. I do it by breaking stuck thinking. You want to sell McDonalds burgers, go ahead. I want to tailor my solutions.

    SO, WHAT INFORMATION DO WE HAVE?

    Quote Originally Posted by Mike530 View Post
    Good Morning,

    My wife and I are going to replace our furnace that is located in a hallway closet on the second floor of our home. We are looking at the Amana AMVC8 furnace and the Lennox SL280V furnace. Both are variable speed. Our concern is which one would produce the least amount noise. Our installer says they are both quiet, but we have read that the Amana is pretty loud and my wife doesn't want a noisy furnace.
    Quote Originally Posted by Mike530 View Post
    We have been considering a 90% furnace, but our weather is mild here in Northern California, and it seemed like the contractors thought the piping might be difficult and not worth it for the high efficiency models.
    Quote Originally Posted by Mike530 View Post
    Your right George it has been a interesting process here with salesman. Nobody does a load calculation. So I did my own....and figured out we only need about 35,000 btu's of heat according to the manual J. So that has been real a challenge, is trying to find a quiet furnace for a upstairs closet and that will match a new 3 ton AC. I read the variable speed was the quietest and my wife wanted something where the heat didn't always fire at a %100, because it heated up our kids room way to fast which are right next to the furnace. It is a 25 year old 80K furnace.
    Quote Originally Posted by George2 View Post
    ... I (and others here) was taught to have the H/P kick off at 30-32 degrees. Otherwise, we were told, the H/Ps were not that efficient below that point and to let the gas heat take over. H/P in this area have never been pushed hard by any of the HVAC places.
    Quote Originally Posted by Mike530 View Post
    Yes we are replacing the entire system. It is a split system...single zone. I was thinking of putting in manual dampers for the kids rooms to stop some of the air flow.



    We know noise is an issue.
    We know oversized equipment also causes discomfort (kids room overheats).
    We know noise is an issue.
    We know this homeowner can reason, they are connecting many dots others don't. Homeowner has done a Manual J indicating heating and cooling worst case loads are just about IDENTICAL at 3 tons.
    We know Manual J overstates worst case load, so the MEAT of this person's load is likely to be in the 10-20k btu area.
    We know modern furnaces want MORE airflow per btu, and we suspect duct volume issues at higher BTU's.
    So going from a net 64,000 to a net 54,000 is NOT likely to solve many comfort, or noise issues.
    We know they are also replacing AC.
    We know they are in a climate that high end heat pumps are likely to have VERY HIGH COP.

    And we know that a 2 stage 3 ton heat pump can deliver to the most common conditions this home will see INCREDIBLY comfortably, quietly, and efficiently. When running on low stage, winter and summer, it will need less than 600 cfm. Noise, comfort, duct deficiencies solved.


    ERLA, you probably think people want hot water heaters too. I think they want hot water. You go sell gas furnaces to people who "think" they want them if you like, but don't tell ME to stop because I want to step back and think about design, and give CONSULTATIVE advice instead of selling products.


    I think I'll LISTEN TO THE PROBLEMS and think about design, rather then grabbing the quick sale. I'll help educate away ignorance and help people solve problems efficiently, even if it means thinking outside the box (pun intended) and suggesting solutions they haven't considered.

    If this were me, it would be a 3 ton 2 stage heat pump.
    Last edited by tedkidd; 11-21-2012 at 08:31 AM.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  3. #42
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,161
    metel supply plenums usually have insulation inside.

    I don't see going to the sheetmetal expense for r/a in closet
    under equipment. just seal 2x's, platform, doorframe to walls.

    you also want them to seal the top of the closet with the equipment
    from the return bleow. this is why I mentioned caulking platform at walls.
    and put something at platform so that it seals tightly to door
    when door is closed.
    I usually use a piece of armaflex split open
    and tacked to platform @ door the split in the armaflex goes over
    the plywood platform & is secured to platform on furnace side
    & below in return side of platform. Then use mastic tape to secure it.

    this seperation of top of closet from r/a below is important.
    also..will they be closing in the top of the closet to attic?


    using ductboard to cover louvered door at top to platform is ok with
    me.
    what you have to think about...is seeing the ductboard through the louvers.
    you get better sound absorption with ductboard with black side facing noise source.
    but do you want to see the other side of the ductboard..the fsk silver side..through
    the louvers?
    for the door only, I'd face the foil to the inside of the closet. the black side
    of the flex will be much less noticable than the silver.

    although I've never found it necessary..I've see companies install an insulated sheet
    of sheetmetal screwed to the platform under the unit (from inside r/a) to the bottom
    of the r/a. like a Z with short top and bottom. sorry no pics.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  4. #43
    Join Date
    Nov 2012
    Posts
    14
    Quote Originally Posted by thermojohn View Post
    The XC14 is a quieter unit. It also allows for easier maintenance as the exterior grilles swing open like a door for cleaning. The 14ACX doesn't have this feature. It is Lennox's builder unit to compete with the rest of the other manufacturers.

    The 14 x 25 filter grille matched with a 3 ton system and VS blower will create another kind of noise... Velocity. Need to put some thought to increasing it for several reasons: Noise and filtration efficiency. I'd start with an opening or a combination of filtered openings with at least twice your exisitng grille's area.
    Is that XC14 worth a premium of $1200 over the 14ACX?

  5. #44
    Join Date
    Jul 2008
    Location
    Rochester NY
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    4,721
    Is that XC14 worth a premium of $xxxx over the 14ACX?

    Yes, absolutely!



    No, Definitely not!


    What answer do you want to hear. Erase the answer you don't like.

    If it's noisy and drives you nuts for the next 15 years, will the $xxxx in your pocket be worth it?

    Oh wait, $xxxx won't be your savings. If there is efficiency lost, deduct the energy the crappier unit didn't save from the $xxxx.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  6. #45
    Join Date
    Apr 2001
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    Quote Originally Posted by Mike530 View Post
    Is that XC14 worth a premium of $1200 over the 14ACX?
    That is a question I answer best at your home where I can give more accurate advice. The XC14 operates quieter than the 14ACX. They have the same SEER rating when matched with the same furnace/coil combo.

    If the unit is next to your rear porch or deck where family gatherings enjoy peace, the XC is what I'd recommend. If on the side of the house by the kid's bedroom, ACX... But don't get me wrong, the ACX is not a rattle trap, and really a decent unit for the value in SEER.

    Like ted said, beauty is really in the eye of the beholder, and once you buy the unit, and get it installed, it may have been worth the extra invested, because quiet is definitely a value.

    Didn't help too much, did I?

  7. #46
    Join Date
    Nov 2012
    Posts
    14
    Thanks Thermojohn for the help. I just had the new system installed. We purchased the 14acx and the sl280v lennox furnace. All is quiet. Except the inducer motor is vibrating on second stage. The company is going to replace the motor to to see if it goes away or if that is just the way it is.

  8. #47
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    Quote Originally Posted by Mike530 View Post
    Thanks Thermojohn for the help. I just had the new system installed. We purchased the 14acx and the sl280v lennox furnace. All is quiet. Except the inducer motor is vibrating on second stage. The company is going to replace the motor to to see if it goes away or if that is just the way it is.
    Glad to have been a help. Is the 14acx satisfactory as far as sound level for you?

    Swapping the inducer should do the trick. It is most likely the wheel making the noise. Also, sometimes something will drop into the flue outlet when they're getting installed, and lodge in the wheel causing it to be out of balance at higher rpm's.

    Make sure your equipment is registered to get your 10 year parts warranty. You may also want to consider their extended 10 year labor warranty if you plan to be there for that amount of time for full P and L coverage. Tier 1 plan is what we offer with every system.

    Thanks for letting me know about your results. Have a great holiday Mike.

    John

  9. #48
    Join Date
    Nov 2012
    Posts
    14
    The 14acx is great. It sits right outside of our family room by a little window. Its pretty quiet. They are hoping a new inducer will fix the vibration.....they haven't installed too many of the sl280v furnaces..so they are not sure if the vibration is just normal operation for that inducer during second stage.

    Happy Holidays,
    Mike

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