Noise reduction

Discussion in 'General Discussions' started by Grove, Dec 19, 2008.

  1. Grove

    Grove New Member

    The manual for Comfort-Aire calls for insulation to be installed for noise reduction both under neath the unit as well as within the duct work near the unit. Did the majority of you guys do this? My installer did not and I'm curious as should I push the issue since it is stated in the manufacturers installation manuals. page 12

    The unit is in the open basement which will later be closed off to be a mechanical room. The main floor is all hard wood and the upstairs will be carpet. Other contractors always commented that the unit seamed loud while the compressor was running before it failed. I do not know if the compressor was truly faulty and if it was noisey before failing. Currently the contractor states that the reverse ball valve is stuck and that it is due to the steps they missed when changing out the compressor. Is it possible that the unit sounded loud because the house is mainly empty and still in construction?

    Thanks you,
  2. rw1995

    rw1995 Member

    I would make sure you put the unit on a pad, as most mfg will recommend this. I would also isolate the unit with vinyl bands, on the supply and return, which will isolate the furnact from your ductwork. Mine has insulation on the cabinet, compressor blanket, pad under the unit and vinyl bands enclosed within a utility room in my basement. It is much quieter than my old NG furnace. You can hear the air moving only, no compressor noise.

    I also insulated the floor joists above the unit in the utility room.

    I have a neighbor who placed his on the floor of the main level, downflow unit. No isolation in the ductwork and no pad under the unit, much more noise.

    I would cover all the mfg recommendations, as it will pay off in noise reduction without a lot of costs.
  3. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader


    Properly designed ductwork for the unit's air flow requirements should not require any noise reductions.

    It is most often in the retrofit applications that you find yourself limited and that is when the aforementioned additions make the most sense.

    I've seen the same installation recommendations in many heat pump manuals but I don't know if you can take it any further than a "rule of thumb". And I have a thing about "rule of thumb".
  5. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Sorry but I have to disagree. Isolation boots and insulating the first 5' - 10' of ductwork and vibration pads should be standard procedure on every install.
  6. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Continue to disagree

    And then I have to disagree...because then it should be a standard feature on all conventional systems ductwork as well. There is no difference (unless you want to talk compressor noise).

    That being said, we have flex and vibration on all our systems, but we're not making money off this - our subs are (well I guess we sell the mats). Basically, I won't sell the client something they won't need and this is one of those items that proper design eliminates the requirement for - but I'm willing to change my thoughts if there is a citation by ASHRAE or such that shows an engineering requirement for it.
  7. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Compressor noise and vibration are the issue for me.

    Maybe we will have to agree to disagree :)
  8. Grove

    Grove New Member

    thanks for the information


    Thank you for the information. I'll insist that the noise reduction issue is addressed. I did inform the general contractor on Friday what the manual said and he informed me that he'll pass the information on to the HVAC contractor. Hopefully in the end the unit works the way it should and that I'll be able to get proper service as needed.
  9. Geotech

    Geotech Member

    There should be at the least a 1/2" of blue board under the cabinet first to reduce the vibration noise of the compressor then to keep the bottom of the unit from rusting from the moisture in the concrete manufactors specs or not this is just good practice,besides how much does half a sheet of blue board cost.
  10. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'm with Dewayne on this one.

    "conventional systems" often mean split systems with compressor outdoors on a pad. Packaged geo systems with the compressor integrated with coil and blower in or near living space will need care taken to avoid compressor noise and vibration propagating into living space
  11. Rgausman

    Rgausman Member

    I also agree with Dewayne:

    "Sorry but I have to disagree. Isolation boots and insulating the first 5' - 10' of ductwork and vibration pads should be standard procedure on every install. "

    Every manufacture's installation guide that I have read 'recommend' these standards. These items are a minor cost to system's overall install cost.

    Also installing insulation into the mechanical room stud bays is good practice if the basement is also used as family living space.

    Regarding compressor blankets, is there any negatives in using them regarding the compressor?

    Bob G.
  12. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    My point

    Is that these are recommendations or standard operating procedures (that we do as well) but they are not regulations or codes. Nor are they design requirements in any capacity. So it is hard to put a contractor to task if they don't do it (as per the original point of this thread). This points to better dialogue at the beginning of the job being required.

    My general thoughts on these type items are that if the client/market wants it, I'm all for it. But if the industry creates its own hurdles and additional costs without thought, than we are making it harder to compete with the conventional world that doesn't even think about such items.

    But I would pose the serious question, why insulate the ductwork (in conditioned spaces)?
  13. Geotech

    Geotech Member


    :)It does not matter it's good practice to isolate a unit from a floor no matter what kind of floor.Geo equipment has a compressor in it and a 1/2" piece of blue board not only isolates the unit from the floor it also helps support the bottom of the unit where the compressor sets.Also this keeps moisture from concrete floors from getting to the units bottom so it will not rust over the next 20 years.Hey it's just the right thing to do.:)
  14. Rgausman

    Rgausman Member

    These are just my personal thoughts...

    Most of the residential codes are in place to address the minimum safety of the construction not the longevity/environmental/comfort/economic performance of the construction or installation of geo heat pumps.

    The big problem with geothermal heat pumps installs is that the customer has certain expectations verse the designer/installer expectations of a system design and performance.

    Designing the system from home owners expectations of energy cost saving, comfort, system reliability and noise are reasons why they decided on GHP in the first place. These are things they have usually been verbally promised for a new system during the intial inquiry but are never written into a contract. This just sets the customer up for a bad relationship with the contractor.

    How many contractors out there have performance guarantee in their contacts for minimum EWT during the heating season? May be the contracts should include all the design parameters including the Tstat set point.

    When presenting the installation quote to the potential customer this is the opportunity were you have to sell your system and differentiate your GHP installation from the competition. If you are presenting a bare bone design quote then also present itemized options with explaination to the quoted price which will satisfied the customer's expectation. By the time the customer is ready to sign the contract, they know this project is going to be a long-term ROI. They expect an install that performs as spec and not have to see the installer again after the install is complete.

    I am concern about the geo heat pump industry as a whole by some of the bad installs going in this year. Look at the problems reported by some of the new GHP homeowners on, and this website.

    For example this one homeowner problem which is 24 pages long and still no resolution in sight about low EWT so early in the season:

    My new Geothermal System - HVAC-Talk: Heating, Air & Refrigeration Discussion

    I think a book could be writen on this subject...

    Bob G.
  15. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Excellent points

    Bob G.,

    Some good points here (and likely a separate discussion thread). We have a Scope of Services Agreement that we sit down with the client and initial off various items as we discuss them. You've pointed out a few additional points I'll look at working in to this agreement.

    Of note we use this document to talk about inclusions/exclusions/our responsibilities and client responsibilities. It goes a long way in clearing up future issues as projects drag out over months sometimes and people forget original intentions.
  16. drupnorth

    drupnorth New Member

    loud scraping noise

    This AM I heard a loud scraping noise coming from our mech. room, this is not the first time I have heard this noise. this is new construction and the unit is only a few months old. I followed the noise and saw there was water all the way around the unit, not puddles but wet enough to be noticeable, but as if a leak was present. This sound was like we had at another house when the water softener was going through its cycle. Any ideas on the noise and leak? we have a closed loop system and live in northern Michigan. thank you.
  17. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    I don't know what the noise might have been.

    Is there water condensing on the loop pipes?

    Is your heat pump still working?
  18. drupnorth

    drupnorth New Member

    water leak

    we have heat and I just looked at the furnace again and there is twice as much water around the furnace as this morning. I have contacted my geo thermal company which is GeoFurnace in Traverse city, MI. I have read my manuals and gone on forums such as this one looking for answers. But it seems the more problems I read about consumers having the more worried I become as I think maybe it's this or that. But that noise this morning was scary to me-the system has only been in place a few months. thanks for looking.
  19. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Is the heat pump still heating your house?
  20. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Is the noise repeating? Any sign of wetness / dripping on loop pipes? Could ice formed on (underlooped) loop lines be melting off during off cycle?

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