Ok, finally. Here is the dBs for Abbaka 1400 remote blower with silencer. Vent pipe is 10”. Vents out to ceiling about 30’ from stove top. I used the Decibel X app as recommended. On high: Under stove top, 64.1 10 feet away, 53.7 30’ away, under silencer in ceiling 51.7 On Low: Under stovetop 54.2 10’ 41.6 30’ 39.8 We really like it. Probably the most important feature we put in our kitchen! Can’t stand kitchen smells of garlic and onions and dislike a lot of noise. Thank you all for your input. Sorry it’s taken me so long to get back to you with numbers. I blame the 7 slabs of granite that cracked, broke or were not advertised size. Thanks again for all of the input. Debbie

two things... we both live in extreme climates. 1)we don't put ducts in exterior walls because of heat gain, you for cold gain. 2)we install ductwork on interior walls and blow the air to the exterior walls. old school (25+ years ago) locating supplies in ceilings next to windows was standard. the grills would blow the air to the window. nowdays we have more knowledge..if we take advanatge of educating ourselves..and understand that blowing warm air on a cold window leads to condensation. with better supply grills we can put the air exactly where we want it to go. gotta love 4 way supply grills! putting ductwork inside conditioned space in false boxing over cabinets..or building boxing (fur downs) might work in your application. it mostly depends upon the layout. if the closet you plan to use is centrally located, the the bottom of the closet is return, the middle is equipment, and the top supply plenum & ducts. with this configuration you need to determine if there is a pathway to serve all rooms. having that simple drawing of the layout would be helpful. if you can't post it, email it to me & I'll post it for you. would a mitisibushi mini split heat pump meet your requirements? "an after thought if I can find the highest blower I can get maximum cfm could I get away with all ceiling registers?" how? build fur downs at ceilings for ducts? not quite clear on this after thought! how's the temps there today??..we are in mid 60's.. a little cool spell after high 70's last week. best of luck.

a long winded description follows. Here is a summary: We have both low frequency (20 to 33 cycles per second ) and high frequency (50 to 60 cycles per second) vibrations. The mats cut down the higher frequencies (although they still let enough through to create noise) , but do nothing to block the lower frequency vibrations. The loudness of the noise is created by the rubber mat underneath my hvac unit which is covering the entire surface area of the bottom of the HVAC unit and the floor below - thus amplifying the vibration. The insulation we put in the walls and the ceiling below is working - but it is cutting down the acoustic noise (noise created by compressing air) - but batt or blown insulation does nothing to block or dampen noise caused by structure vibration. The problem can be solved by removing the rubber mats and replacing them with 4 vibration isolators - which are essentailly leg supports with springs - under the 4 corners of the unit. There was a recommendation to suspend the HVAC unit from above. This could be done but is probably not necessary. I will keep you posted on the progress. *************************detail In my quest to understand the physics of what is happening with the my hvac vibration on the second floor of my home under construction, I stumbled data sheet that has some interesting info in it. See http://www.b-line.com/product/PDFLibrary/pipehangers/index.htm. Click on Vibra-Trol and then the Introduction. Download the PDF data sheet. The table on the second page shows the amount of vibration reduction as a function of the deflection of the vibration cancellation device used. If you look at the left most column in the table - the 1/16th inch deflection corresponds to what you get with a rubber mat or neoprene pad. The N/R means not recommended. The HVAC unit we have on the second floor operates in the 1200 to 2000 RPM range (or 20 to 33 cycles per second). If you look at the table you can see that the vibration reduction by a mat/pad in that RPM range is not very good. The Econar units also have a Compliant Scroll compressor. I checked their specs and the unit runs in the 50 to 60 cycles per second range (or 3000 to 3600 RPM). You can see in the table that mats or pads are OK for these higher RPM rates - but not the best. They would still allow 10 to 12% of the vibration through the mats at these higher frequnecies. You also have to consider harmonics - which are additional frequencies generated at +/- 1/2, 1/3,1/4, 1/5 etc of the center frequency of the compressor. If the amplitude of the vibration of the center frequency is high, harmonics at lower frequencies will also be high. That means the harmonics at lower frequencies can also pass through the rubber mats. If you look on the right hand side of the table - you can see what the noise reduction is for spring mounts (you can see an example of one of these on the cover of the attachment - left hand side of the picture with yellow spring and bolt sticking up). A spring device with a 1" deflection provides 97 to 99 percent reduction in vibration for the lower RPM ranges of the fan, the higher RPM range for the compressor, and the harmonics at low frequency created by the compressor. At the bottom of the data sheet - they provide a calculation on how to size the springs based on the weight of the equipment. The corner load is 1.25 times the unit load divided by 4. The spring mounts are not terribly expensive, maybe 10 to 20 dollars each. The springs themselves (depending on the brand) are about 3.5 to 4.5 inches tall with no load, and about 2.5 to 3.5 inches tall when compressed with a load - assuming a 1 inch deflection - which should be adequate for our problem.

Wow! I never would have guessed this. One can only imagine why the HVAC contractor did it this way. Typically this is how fur down unit would be installed. They install the fur down unit inside the plenum or return if you will. However, this unit is not a fur down unit. It could work, but noise will probably be a factor to some degree because it appears to me the return is not large enough. So why did they do this? Maybe there were no better options? I noticed from the original post there is an optional tray ceilings. Do you have the tray ceilings? If you do have the tray ceilings an attic install would be more difficult to put hvac in attic. The closet where this sits is off to the far side of the home maybe for whatever reason there is not enough room to run a return back up thru the ceiling in this closet due to roof joists. Looking at the picture they put a small return grill in that closet off center. The contractor may have been forced to do it that way... no room equals no room. Architects really mess things up by not thinking. It can work this way, but it's not ideal... because air is stupid. When that unit kicks on it will draw air from where ever it can. Thru cracks and crevices in that door leading out. It's common knowledge that doors leak. If you put a louver on that door, then there is no filtered protection to that coil (unless they put a filter at the coil it's a poor way to do it. Plus then you create a wind tunnel, every time the unit kicks on there's this rush of air going to the laundry closet and on into the HVAC closet. What makes it even worse is the garage directly behind the unit. If there are cracks at the base of the wall / thru electrical plugs you have the potential of sucking carbon monoxide into the home if a vehicle is running. It would be prudent to check this. The filter you show out in the hall is big, the one in the closet is small it is likely these two are connected... that is your return. Problem is the return in the room of the unit is in the shape of a funnel (goose neck) the system will never have enough air because of that. The contractor either messed up or the architect or a combination of the two. Certainly they will tell you any alterations will void the warranty, because many in this business do not understand simple things let alone the more complex things like the design of your system. A year goes by pretty fast though, if you still have too much noise I would keep complaining. The noise tells you a problem exists, don't let them tell you otherwise.