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hood with remote/removed motor?

Posted by ellekay (My Page) on
Wed, Oct 19, 11 at 23:24

I am purchasing a 36" 6-burner Capital range and need a hood. I recently heard about this concept of a hood that can be much quieter because the motor is at some distance (like on the roof) away from the hood. We will be venting through the ceiling to the roof.
Have you heard of this? Does it work well? Can you recommend a brand to consider?
I was thinking of getting a 27" depth, though also wonder if it is going to be too annoying for my 6'4" spouse.
Thank you for your input!


Follow-Up Postings:

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RE: hood with remote/removed motor?

Remote fans work well but they need a minimum duct run of about 7 ft but is really situation specific. You also need a silencer, the fantech L10 is very popular and only $140. It is for a 10" duct which is what you wan't in this siuation.

Along with Independent and Prestige Hoods,I think the Eurostoves hood by Modern-Aire is top notch. It can be made to 27" depth. Can't answer the question about the world view of a 6'4" guy.

If you buy a Culinarian and Euro-Stoves hood this month you get $1000 off. Link to euro-stoves Culinarian site below. I would definetly contact them and discuss your issues.

Here is a link that might be useful: LINK


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RE: hood with remote/removed motor?

"inline" is the key word for Fantech and for this forum.

You do not need a silencer.


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RE: hood with remote/removed motor?

If you want the quietest result possible then you need a silencer. Relative to the cost of hood,blower,and installation it is cheap.


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RE: hood with remote/removed motor?

both good points, in theory and in terms of budgeting for a massive $ installation. I got an inline Fantech blower, and installed it without the silencer. I would have been willing to order a silencer and install if I have found the noise to be unacceptable. (I didn't skimp on anything and ordered everything else I wanted for my kitchen renovation.) ellekay it all depends, so post again about the details.


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RE: hood with remote/removed motor?

I just went through this myself. My plan is to go with a Modernaire hood but haven't picked that out yet. I was more concerned now getting the duct work in place. I have been doing allot of my project DIY and just turned this part over to the HVAC guys to finish it up and save time. I need to get my house closed up.

I had originally purchased the Fantech FKD10XL fan, silencer, clamps, roof cap, backdraft damper, etc. I was up to the point of mounting the fan, when I ran into questions. You really want the fan as close to the roof cap as possible and you want to have it a good distance from the hood. In my case this meant installing the fan vertically. The manual states to use vibration isolators but you are on your own with that one. Even fantech was of little help here. horizontal mouting options and isolators are much easier. I then also realized that many people say this fan sounds like a jet plane taking off, I assume on high due to the volume of air it moves. Not sure I would ever run the fan on high and I installed a silencer which would mitigate noise on the interior but.. not sure how this translates into the noise on the exterior. I ended up shipping the fan and roof cap back and paid additional $$ for the Abakka Roof mounted fan. It has a low DB rating. I will be running the electrical to that fan this week and then power it on to test. My attic over the kitchen is small and once insulated is not easily accessible. So mounting on the roof was a better option since it can all be serviced from above. This is something to consider as well. It is a pretty low profile and I got mine in a powder coated black finish only because the galvanized was out of stock. Love the color and blend nicely with the roof.


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RE: hood with remote/removed motor?

In my last 2 houses we installed (small) microwaves above ranges. The microwaves have hood and fan built-in and discharge through the top. Above the micro-=wave then we have a (small-size) cabinet with the pipe from the microwave through it to the outside. Noise is of no concern here, very little noise.


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RE: hood with remote/removed motor?

I went with the Modern-Aire 40 inch PSL liner for a range hood that our cabinet maker is building over the same range you have. We have very high ceilings in the house, so the ten inch duct goes up from the insert, into the attic, over to the Fantech FKD 10XL, with one of the Fantech silencers (the size of a small garbage can) in between. It's a short trip from the fan outlet up through our roof.

Cabinets begin going in this week and we don't have power in the house yet, so it'll be a month or more before I can give you a SITREP on how it all works.

I'm 6'4" but didn't specifiy the 27 inch depth. I don't have a grill on the range, and the edges of the hood will be flush against cabinetry on both sides, so I'll have pretty good capture as it is. The attached shows the cabinet maker's plans for the hood, surrounding cabinets, and duct cover. The cutouts on the right are for the Miele Speed Oven and Warming Drawer with trim kit.

BTW, the Fantech fan is way above the nominal/calculated requirements for the range. I just like the idea of having more capability on tap through the infinitely-variable switch than maxing out with a smaller fan and smaller diameter ducting. Like horsepower, I think it's better to have it and not need it than it is to need it and not have it.

Here is a link that might be useful: Range & Oven Cabinet Plans


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RE: hood with remote/removed motor?

"""hood that can be much quieter because the motor is at some distance (like on the roof) away from the hood."""

This is partially correct. The hood isn't quieter because the blower is farther from the hood. It's quieter because remote blowers are usually bigger, can move more CFM's and therefore require larger duct size's like 8 or 10 inch round. Air moving through a duct will generate most of the noise you hear at the hood, not the noise from the blower which I find insignificant. Like a hum. However, duct size has a direct correlation on noise. The same amount of air moving through a 6 or 7 inch duct will make more noise than if it was going through an 8 or 10 inch duct.

Also, with any motor(blowers are motors), the larger it is, the quieter it is on a low setting. Therefore, on low, you probably wouldn't hear a hum on a remote blower.
This also means that when cranked up to high, it is noisier because it is larger.


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R1E: hood with remote/removed motor?

The kitchen exhaust hood experience IS quieter when the blower motor is farther away. This is true because the motor itself makes noise. All motors.


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RE: hood with remote/removed motor?

Davidro. You are correct, all motors make noise. However, in my experience with Best, Broan, Jenn Air, Wolf, Dacor, and Miele, the internal MOTOR noise is indiscernible in relation to the noise the air makes, even on low settings. Although just a small sample of manufacturer's, I feel this gives me a good frame of reference.

This doesn't apply to Vent-a-Hoods, a whole different animal and not relevant to the post.


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RE: hood with remote/removed motor?

Why not go with an external fan? It seems to me that would eliminate all the issues with needing a silencer and vibration isolators. Plus it will be easier to fix if something goes wrong.


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RE: hood with remote/removed motor?

I believe that in a system with quiet, well-balanced fan, in-line silencer, large-enough ducts covered with dampening material, the dominant ventilation noise at higher flow rates will be turbulence induced noise at the baffles or mesh, whichever is used as a large particulate filter at the hood. However, this noise may be expected to be partly masked by the noise from the type of cooking that would call for enough cfm to induces turbulence noise, i.e., frying, wokking, or grilling.

kas


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RE: hood with remote/removed motor?

" .... It seems to me that would eliminate all the issues with needing a silencer..."
no, no, they will sell silencers for external motors too. If it fits in the duct run, they'll sell it to you.

vibration isolators are just pads. Good to have, good to use. Any motor installed anywhere can be mounted in such manner as to isolate its hum from vibrating the building structure.


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RE: hood with remote/removed motor?

I will chime in here with a bit of measured data on the Fantech LD10 duct silencer. I will be installing one, with a Broan 331H 600CFM roof mounted blower, and a Broan E60E35SS (36") hood, with 10" duct all the way.

I set up the following experiment:

First, the LD10 , which is 3 feet long. My wife held her hairdryer at one end of the duct, facing out. i.e., pulling air from the duct. I measured the noise level, A-weighted and C-weighted, at the other end.

I repeated the test for a section of regular 10" duct, 5 feet long.

Results, dBA / dBC :

Fantech LD10.......73 / 76
Regular 10 inch.....94 / 96

Attenuation results are pretty much in keeping with the specs on the Fantech site.

Subjectively, MUCH less noisy with the LD10. The resulting noise was more like a hiss, which tells me that the lower frequencies were more attenuated than the higher ones.

BTW, the motor noise in my wife's Viking hood, internal 435CFM, is quite obvious even in the context of the air noise.


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RE: hood with remote/removed motor?

Air turbulence shed from the fan blades (particularly in the higher speed regime) is a fan noise that can be attenuated with distance. Nearby duct noise and hood baffle noise and hood-to-duct transition noise will not be.

Nice work attofarad with the data. I suggest that the finite length of the silencer will establish a lower frequency limit to attenuation. The hiss may be due to the hard interior perforated wall dominating at extremely high frequencies. A silencer effective for very high frequencies might have a problem with grease.

kas


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RE: hood with remote/removed motor?

I'm thinking that once the frequency gets high enough that the wavelength is considerably less than the cross section (10"), the higher frequencies just pretty much go through the silencer without much effect. So this would start decreasing effectiveness around 1400 Hz. Counter to that increase in noise (decrease in silencer attenuation) is that higher frequencies are more attenuated in air (or solids) than lower frequencies. Fantech shows the best attenuation at about 2kHz for the 10" LD10.


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