Wolf baffled hoods are of the same general design as Prestige and Modern Aire baffled hoods. One might say that they are all an attempt at performing the function of commercial hoods with the efficiency of commercial hoods while achieving a higher level of aesthetic design. As such, they incorporate various trade-offs that for the most part are compatible with residential use.

Choosing between them would be a matter of appearance and cost. I am quite satisfied with my Wolf hood (built for Wolf to their spec by Independent ca. 2007). I think it is safe to write that generally this forum's members suggest manufacturers such as Modern Aire that can provide tailor-made configurations when the poster has a need that isn't met by a stock hood design. Otherwise, many different hoods provide a variety of features (including lower cost than the high-end) and are often recommended for particular applications. I do not recommend specific manufacturers' hoods that I've never owned.

A roof blower assembly and an in-line silencer is equivalent in function to an in-line blower assembly and in-line silencer. The silencer needed is determined by the duct size. An LD10 is for 10-inch ducts. You may only need an LD8 or whatever goes with the duct size needed by your hood and blower.

If you want to avoid too much design detail, choose the largest Wolf blower that is recommended by them (at the back of their hood brochure) to go with your selected hood. Alternatively, having chosen the hood (and I"d recommend it be wider than the cooktop by at least six inches if it can fit and as deep as tolerable), calculate the aperture area (the inside capture area not the outside of the hood), convert to square feet, multiply by 90 cfm/sq. ft., further multiply by 1.5 because it won't be running at zero static pressure, and select a blower that is rated (at zero static pressure) near that resulting flow rate. (There are make-up air issues that come into play that you can find in topics here, or ask about when your selection is tentatively made.)

The Wolf hood probably has a damper. A down-slope roof blower assembly made by Wolf (actually, probably for them by Broan), or Abbaka, or Broan will have a damper. If an in-line blower is used, than a damper will be needed on the roof side, as well as a suitable roof cap for the ducting. For most, the roof blower is the simplest solution because it provides all three elements. Special cases arise if one is subject to very deep roof snow.

Note that selecting a blower and hood from the same manufacturer will assure that the fan control in the hood is compatible with the blower. This may not be the lowest cost approach if your time is free, but it moves the engineering to the supplier.

It is my observation that those here that have built a configuration based on a remote blower, in-line silencer, and non-blower hood, have concluded that it is quietest for a given flow rate/hood size. We rarely have any way of direct comparison to make an unqualified assertion.

Several years ago, a member of this forum had two houses, one with a Vent-a-hood (of that time) and one with the configuration above, and made sound measurements with the same sound meter in the same way and found the Vent-a-Hood to be significantly noisier. I think this member was clinresga. We have no way of knowing what the result would have been if there were no silencer. You may be able to find the threads.

Since then it is possible that VAH have modified their design for lower noise, but since blade tip turbulence is the dominant noise, and the VAH puts that right at the cooks ear, it would be hard to beat a silenced remote fan, where the remaining noise is baffle turbulence noise. Baffle noise could also vary with manufacturers' designs, so it is doubly hard to compare unheard baffle designs with each other or with the leading configuration competitor VAH's designs. Further complicating this is that the turbulence is proportional to blade size and tip velocity, so if room allows, a larger slower fan could be used and be very quiet. Going too far in this direction is not practical to fit, but as Admiral Rickover once said: "The devil is in the details ...."

kas

Wow!!! Thanks so much Kas!! Your response is very helpful!!

I don't have enough room to put in a hood greater than 30 inches due to existing cabinets. The Wolf hood I like recommends 10 inch duct work which is why I thought the LD10 silencer would work. What do you think about the 6 feet of duct run from my hood to the roof? Is that enough space for the silencer and the blower?

you might want to check the specs again. I have never heard of a hood for 500cfm with a 10" duct. Normally its 600cfm = 8" duct or 1200 cfm = 10" duct.

The problem you have i think is the fantech silencer is 3' long for the 10" duct, unless your going straight as an arrow that might not work. the 8" duct is a 2' long silencer.

If this was my job and you wanted soup to nuts here it is

Hood 6" wider than your range.
27" deep if possible.
Remote roof blower 1000 cfm.
In-line silencer.
Damper in between the hood and silencer.

@Trevor....I just checked the specs again and Wolf does recommend a 10 inch duct for their pro ranges. I am considering the 600 cfm blower. Why do you prefer the remote blower over the inline?

With respect to the duct diameter:

There have been rules for commercial kitchen ventilation ducts that attempt to minimize the amount of grease that condenses on the duct walls (a bigger problem for commercial kitchens than residential kitchens, but still relevant). The goal was an air velocity of 1500 ft/minute, as I recall. Commercial systems typically run at one speed, so this would correspond to full power. More recent study suggests that higher speeds are better for warm ducts, and lower for cold ducts to reduce duct wall impingement due to turbulence.

In any case, the flow rate (CFM) divided by the duct cross-sectional area (sq. ft.) yields velocity in ft/min.

What will the flow rate be, he asked? Well, we might guess that a 600 cfm rated blower having to pull/push air through a duct at 1000 ft/min and through hood transitions, the silencer, and the baffles, against some (hopefully small but unlikely to be zero) house negative pressure, will only move an amount well under 600 cfm. One would need a fan curve to calculate net flow rate, assuming that one knew all the losses including the baffle loss as a function of flow.

Lacking that, I would assume maybe 450 cfm max, given a screened open window equivalent for the MUA, and that the duct is fairly short. 450 cfm in an 8-inch duct (0.4 sq. ft.) is 1125 ft/min -- a good value for the desired span of flow velocities. I wouldn't use a 10-inch duct unless there were a near-term intent to upgrade the range and the hood to a larger size. You can fit an 8-inch silencer more easily into the six feet of duct length that you have.

With respect to in-line vs. roof blowers: In this case where there is not a lot of duct length to play with, the possible need for offsets to get the blower away from the edge of the roof, and given the weight of an in-line blower that would have to be supported somehow in the duct length, and maybe some day repaired, I would tend to prefer a roof blower, unless there were some overarching reason for not mounting on the roof.

kas

P.S. Most pro hoods are somewhat larger than you are specifying, and for them a 10-inch duct would be suitable. I would be surprised if this specific hood even had a 10-inch cut-out in the top.

I have the largest Pro Island hood that Wolf sold in 2007 and it uses a 10-inch duct with a nominal (but certainly never achieved) 1500 cfm roof blower. If your hood actually needed a 10-inch duct, mine would need a 14-inch duct, a size that would be a real pain to integrate with a silencer, offsets, and attic space.

kas

P.P.S. The Wolf PW302210 is specified for both 600 and 900 cfm remote blowers. Per page 126 of the Wolf Design Guide, the 600/900 roof blower has a 10-inch duct interface.

Page 124 specifies that Pro hoods have a 10-inch interface.

My view is that a 10-inch duct is overkill for this most modest of all of Wolf's hood sizes. But given that the interface is 10-inches at each end, the simplest ducting solution is 10 inches. However, one may find that with this size and using a silencer, there will be no easy straight up through the attic solution, and that some offsetting will be needed.

Alternatively, 10 to 8 and 8 to 10 transitions can be used at the ends of an 8-inch duct run.

I recommend that you get your HVAC person involved early so that the installation difficulties for either size are fully investigated. Joists and/or rafters may have to be cut and reinforcements installed. It isn't the end of the world to go with 10-inch ducting for such a modest flow rate, but it certainly is, as Trevor and I have noted, an unexpected requirement.

kas

I'm a little confused. Does a hood then require three different electrical outlets? One at the hood level one at the roof level and one at the silencer level?

Functionally, the hood is wired to house power; the blower is wired to the hood. Physically, there may be several topologies that are possible, one of which will be best for a given situation. Generally, for the "infinite speed" Wolf (I hope they mean infinitely fine resolution of speed, itself unlikely) a simple semiconductor control like those used on wall switches to dim lights is used. (Mine uses a triac/diac circuit.) The modern approach to wiring is to send power to the control (in this case the hood) and pass the resulting controlled power to the blower. But you can download all the relevant installation manuals and see how they want it configured.

The silencer is like a car muffler, totally passive and requiring no electrical power. It comprises an outer skin and an inner perforated skin, both welded to the duct interface at each end.

kas

The silencer is not electrical.

A silencer works in a similar way to a muffler box on your car.

The silencer is also wider than your duct so make sure you can fit the diameter of which could be pushing 14" - 15"

@Kas and Trevor...I am no longer confused because of your help. I am so appreciative of the both of you taking time to help me. I now have a path forward that I am comfortable with. I made an appointment with a HVAC company to review the options we discussed. Thanks again!!