Thanks Kaseki. I will call Modernaire - I was disappointed when I went through their website and saw that their deepest hood was 22 inches, and the capture volume of their inserts didn't look any better than anyone else's. Perhaps they just don't advertise the ability to make something more custom?

You're right that a tall commercial hood might be a deal-breaker with our 8 ft ceilings. I don't really want to cut a huge square hole in the ceiling, plus was hoping to save the attic space for potentially a silencer or in-line blower...will await further conversations with the Accurex rep, hopefully today! I really appreciate the moral support.

I would be interested in anyone's experience, if they have moved their hood "out" from the wall to get better capture? Worth noting that there will be no "flame" per se, it's an induction cooktop...

You don’t have the combustion products or heat with induction. I’m sure the residential hoods will be fine. I would judge by cleanability first (all specs being equal).

OK everyone, just found this one (why I didn't come across it before I have no idea. Karma again, I just needed to screw up the courage to stop lurking and start posting, and voila all sorts of things are revealing themselves, ha!) Residential, looks like decent capture volume. Though it's still only 22 inches deep, the silly "light bar" is not there so you get the full area for ventilation (they put the lights at the top)- thoughts?

It's by a company called "Prestige" and they're out of New Jersey. Might this be the best match for me? I did a cursory search here and didn't find much bad feedback (at least no worse than anything that gets reviewed on these forums) and a lot of good. Still planning to call Modern Aire but this looks promising too.

Start your planning from the induction cooktop's installation instructions w.r.t. combustibles. Note that baffle and mesh filters used in hoods have being a firestop as one function, and this is not to protect against gas burners, but unintended flambé's, quite possible with induction because of the tendency to turn them on and do something else while they "warm up" the pan.

Moving the hood out from the wall has been a topic here intermittently for several years. Some examples might be found by searching, but the best search term is not obvious to me at the moment.

Many commercial hoods do this in reverse, they use a large hood entry aperture for full capture, but taper the interior to feed a single row of baffles. They may have higher baffle noise per square foot of baffle assembly, but the baffles are farther from the cook.

Yes. Baffles need a certain amount of air flow velocity to work properly. Too little and the grease does not get removed so well. This varries by design. I suspect that some (many?) consumer hoods are not designed by engineers or at least engineers who understand this as many seem to have too much baffle for the air flow (which I assume is a poor attempt at reducing noise).

OTOH, I'm not sure how critical grease removal is for residential.

The most important thing that ventilation does is remove grease. This is what ends up floating around the kitchen/home and lands on the cabinets, countertops, carpets and leaves the wonderful smell of breakfast there when you get home at the end of the day. Opaone is correct about the airflow for baffle filters. For these to work properly they require high velocity air pulling the cooking contaminates through the filter. This is why most people turn down the blower so it is at a tolerable noise level but doing this makes the filters almost completely useless. I have had Vent a Hoods in a couple different homes over the years and they work great. They have the large open canopy to hold the cooking vapors while the blower removes the grease. The easy clean system they came out with made cleaning quick and easy. I pull down the tray once a week and clean out the grease and a couple times a year pull down the box around the motors and clean the wheels and the inside of the box and wipe the inside of the hood. Takes 15-20 minutes every 6 months or so, no big deal. Much easier than cleaning the grease that gets behind the baffle filters and up inside the hard to reach parts of the hood behind the filters.

"The most important thing that ventilation does is remove grease."

NO. The most important thing that ventilation does is remove PM, VOCs, and Carcinogens.

You guys are writing at cross purposes. @opaone was addressing the value (in residential use) of baffles to remove some of the grease particulates at the larger size end of the particle spectrum, versus not bothering to do so (thereby causing a bit more grease capture on the ducts). Please observe that elimination of the capture requirement imposed on the baffles won't remove the need for baffles because they serve as a fire stop.

@regbob you seem to be addressing removing grease particulates from the room. I think we all agree that removing cooking plume effluent -- usually dominated by grease and moisture -- is a good and necessary thing. Addressing how perfectly this has to be achieved might devolve into an argument about threshold health damage levels, lack of double-blind lifetime testing to find them, and related issues which seem to lead to some umbrage when argued.

In this regard we should not forget that typically opened ovens that have been cooking meat will spill a lot of effluent into the kitchen due to the difficulty of capture and containment. One such spill might equal a week of cooktop searing with 90% capture. Providing large commercial hoods over all cooking devices will require significant conditioned air flow, and somewhere the power needed is being partially provided by power plants that are less than ideal at avoiding all of opaone's "NO" list that they generate merging with the atmosphere.

The best we can do is attempt to maximize capture and containment performance within the limits of cost, aesthetics, and architectural limitations.

Well said. I do not want anyone feeling like they need to get too detailed on the relative merits of grease, VOCs etcetera. Let's all agree that none of them is desirable, and we do what we can. I am interested to hear the favorable review from regbob on the vent-a-hood, and wonder if there is more we can hear (without kicking off a fraught discussion, just a friendly and informational one!) I thought the "squirrel cage" thing was hard to clean? Plus I hate the name, squirrels are a mortal enemy in our garden :)

I can relate that the VaH design removes the pressure loss of baffles as they are absent. Pressure loss degrades blower CFM performance. But the VaH hood system still has to deal with duct and MUA pressure losses. Based on data at VaH, the squirrel cage blowers are not as good at keeping CFM up when subjected to pressure loss (back high pressure, front low pressure) than conventional centrifugal blowers, such as Wolf, Broan and Abbaka use on roofs and other applications. Nor are they as good as axial fans used in some in-line blowers (relatives of aerospace blowers). So, one has to ensure that duct length is short and/or diameter is large, and that make-up air is not restricted, perhaps requiring a blower system of its own.

Note that squirrel cage as a fan design, precedes VaH corporation by decades, perhaps even centuries if water wheels are counted. As a name, it likely arose when rodents were first kept as pets and needed exercise.

With respect to cleaning, I don't have a problem reaching up into my Wolf hood to clean the interior, while my baffle assemblies are being degreased by the dishwasher.

If they had said "The most important thing that baffles do..." then that would have been a correct statement.

As to VAH. They are likely the worst overhead system you can buy (but they do have great marketing and spiff sales folks well). If not cleaned very frequently, like monthly, then performance degrades quickly due to buildup of solids on the fan blades. They can quickly fall to below 50 CFM. They are very loud per 100 CFM and this gets worse as solids build up since noise remains about the same (actually increases slightly) but effluent removal declines.

From a subjective standpoint - we had one and disassembling, cleaning and reassembling it is much more work than baffles.

See Noise here: https://bamasotan.us/range-exhaust-hood-faq/

"In this regard we should not forget that typically opened ovens that have been cooking meat will spill a lot of effluent into the kitchen due to the difficulty of capture and containment. One such spill might equal a week of cooktop searing with 90% capture."

Good point and this would be something worth more study.

On our current RNB and our two previous Wolf's (range ovens) a lot of the oven effluent exhuasts out of the backguard while cooking and nearly 100% of that gets exhausted by the hood (so long as the hood is on). How much remains in the oven to come billowing out when the door is open would be interesting to find out.

The biggest bursts of effuent (over any time period) are typically when something hits a hot surface (first placed on, flipped, etc) so something simply cooking may not produce very high levels of harmful effluent.

I should have written broiling meat, but will note that even baked chicken has odor, and with cooking odor are usually grease particulates.

If one were broiling steak in a range under the hood, and some effluent is carried up via the back-guard, doesn't yet more spill out when the door is opened. And this spillage will be wide of most hood systems, other than yours @opaone.

We need to be careful not to let perfect be the enemy of good, where in the hood world perfect is unaffordable and generally too large to fit in most residences.

I think I can give a couple of reviews on the VAH products. The first is the traditional vented hoods. I had 2 in the past at different houses. I went with both because I believed in the grease removal and the noise levels. As far as cleaning I had both options. the first hood had the older style housing where the grease was collected in the housing around the motors. This was not a big deal. I would take the box down and soak it in the sink for a while and clean out the grease. the only "problem" I found was the water collected in the box and the first time I cleaned it I did not allow for this and water came out when I went to put it back in the hood. I solved this just by letting the box sit in the sink for a while as I was cleaning the wheels and the inside of the hood, easy fix. Cleaning the wheels was not that bad. Depending on how bad they were they could be left as is. When they did need to come off for cleaning it was just a simple set screw that let them come off. Now this is the one thing I will admit is a bit of a PITA to do. You need to be a bit of a contortionist to get up in the hood to get to these if you are taller like me but it is something that is done once or twice a year. When the wheels are down i would just throw them in the dishwasher and they were good to go. Putting them back on was easy, the motor shaft has a clip on it that gets the wheel positioned correctly and then it was just a matter of putting the box back on and you are ready to go. My second hood had their easy clean tray, this was a great improvement. the tray would slide on and off the box with the grease collected in a small tray. Pull it down once a week wipe it out, slide it back on and you are all set. With the collected grease dipping into the tray the box did not need to come down unless you wanted to see what condition the wheels were in. Over all pretty easy to do once or twice a year for a good deep cleaning.

My second review is on their recirculating hood. I moved into a townhome 2 years ago with an OTR microwave/vent. After having any kind of a decent hood this had to go. I looked at their ARS hood and it uses the same grease removal system with the charcoal and dense paper filter to clean the air as it passes through. I was pleasantly surprised with the performance. The grease removal is great, it collects in a tray under the blower that is held on with a couple buckles so it is a quick and easy step to pull the tray down and clean out the grease and wipe down the inside of the hood. The smells and smoke are taken care of at a 90+% rate so not bad for a non-vented hood. I also put in an induction range and after a quick learning curve of walking away when I should have stayed at the range I had a couple of bad burning experiences so lesson learned. For a recirculating hood compared to a vented hood I would give it a B+, venting outside is always the best option but if it cannot be done the VAH recirculating hood is the best option available. The price is a little high but you do get what you pay for and nothing will ruin a new kitchen faster that having bad or no ventilation. Hopefully this will help out people with questions, I just gave my opinions on my experiences and what i found after looking at all available options when I was in the market for appliances.

Had a Kobe hood insert for years, loved it. It was very quiet and had baffles that could be easily removed and cleaned. Read about them here on gardenweb years ago in the kitchen forums...that was about 2005ish...

Jean I am so glad your Kobe has worked well! Ironically I put a Kobe in our current kitchen (Gardenweb class of 2011) and while good looking and easy to clean, and also muuuch more hood power than anyone else I know, it has been inadequate for our range (which admittedly is a high btu gas range). it is not full depth, plus the light bar (I know I’m repeating myself) so really only works well for the back burners. so I do all my wokking and searing back there, but I am not getting younger and the ergonomics of back burner cooking are not ideal :)

regbob thanks for the comprehensive overview o fthe ventahood, probably the best one on this forum in recent memory. Although I am now strongly leaning towards either Modernaire or Prestige, your post is such a good resource!

@gardengrl66 z5 did you end up learning more from Modern-Aire regarding custom depths? I'm considering contacting them myself, thinking about replacing a 36" x 24" deep Elica that...kind of just isn't working.

I looked up Prestige because you mention it as a top contender in this thread and it seems like they actually sell 30" deep hoods, called Pro Line High Capacity (https://www.prestige-america.com/prolinehighcapacity). That's a depth I haven't seen in any other residential hood I could find plus the extra benefit from their smarter light bar placement, I'm actually surprised they haven't gotten more attention on the many long Houzz ventilation threads. Curious for @kaseki and @opaone thoughts on these -- they seems like they should have a significantly better capture area profile than most (residential) hoods, unless I'm missing something?

d7sharp9, I actually am trying to go with Prestige for all the reasons you stated. Got a very nice person on the line, but they are being kind of slow on getting a couple of my questions answered and sending a quote...as far as Modern-Aire, here is what their rep said in response to my question about getting more capture volume:

"We do not currently offer different mounting angles for our filters. In addition, the filter size does not increase after the hood is 27” deep or greater. You could use our PML liners with mesh filters in which case the length of the filters continues to increase linearly relative to the depth of the hood however those filters are spec’d to lie horizontally"

And they do not offer anything standard in greater than 24" depth but it sounds like they would do one custom. I just don't see the point if Prestige can get me one. I have to bug him again tomorrow, as this is becoming a rate limiting step in moving forward...hope that helps!

I have zero insights to add on the hood, but if you are this knowledgeable and researched focused on hoods--can you share which 36 induction you chose and why? Thanks!

Well I got a Wolf, partly because they are pretty well-reviewed here - see many threads - but actually mostly because of the burner configuration. Namely, the big burner is sort of off to the side (it shares "vertical" space with the controls). All the other brands seem to put the large burner in the middle, where it sort of looks like it is crowding out the others. I do a lot of canning in the summer (gardening addict as my name implies) and soups/stews in the winter, and I think I will like having the canner in its own space, so I can get on with other cooking duties on the other burners without having to work around the big pot. Currently I have a 30-inch Capital gas range and the canner does take up a lot of space, such that it is hard to get other big pots going at the same time. Same for the wok, actually.

I don't want this to become a thread too much about cooktops though. So far I think we are learning a lot about hoods for those of us who do not have the bandwidth to go for "perfect", but enjoy advice from those who do! Keep the feedback coming!

My Frigidaire Gallery 36-inch has the largest hob by itself on the right (with its own generator). Controls are at the front center.

@d7sharp9: I concentrate, as time allows, on writing about ventilation requirements rather than what the latest design is from the many hood manufacturers. If there are good reviews of a hood, I may recall them for passing on. I noticed in the Wolf Design Guide that they make various widths of "outdoor wall hood" that are 33 inches deep (probably 30 inches aperture-wise). I'm sure it is as shiny as the interior versions.

More front to back depth is good, but such a protrusion not only has to pass the spouse aesthetics test, but also the spouse head bumping test. It should probably be mounted at 40 inches for so (Prestige notes 42), and overlap the cooktop by more than 3 inches on each side across the width. Given a specific hood air velocity over the intake aperture, then such a hood will require more hood system CFM and counterpart MUA CFM than a 24 inch deep hood, and this may need to be heated.

Example: 36 inch cooktop, 48-inch width, 30-inch depth, capture area 10 sq. ft. Blower 900 CFM at the pressure losses present, or 1350 or greater rated flow rate. I'd probably just go with the 1500 for Wolf, 1600 for Prestige roof mounted blowers. Most of the time one can operate at partial power and stay very quiet. 10-inch duct will work, but for extended runs I'd use 12-inch. Where space permits, a Fantech silencer of the appropriate diameter will greatly reduce noise.

@d7sharp9, good find on the Prestige. Added to the FAQ.

From what I can see it would be far better than any other consumer hoods I'm aware of. Very glad to see this.

"More front to back depth is good, but such a protrusion not only has to pass the spouse aesthetics test, but also the spouse head bumping test."

:-)

The benefits of a larger hood placed over head height are numerous and I never want to go back to a shallower depth at a lower height. First is that it's simply much more comfortable to have it up and out of the way. Lighting is much much better. Aesthetically we found it actually works better as it balances well with the range below (much to the pleasant surprise of our interiors folks).

If the hood has adequate containment volume then it will need less CFM, not more (E.G., why our large commercial hood needs lower CFM's than consumer hoods).

Yes on containment volume, but you will note that the Prestige images at the link show the same general configuration as my Wolf Pro Island hood. Larger size, more containment volume, but it is not in the ballpark of a commercial hood where the baffles are farther up in a larger structure.

I forgot to note that the Wolf outdoor hood is 18-inches high, and if mounted at 42 inches above the counter will need a minimum of an 8-foot ceiling. Ditto the Prestige "High Capacity" hood. Commercial hoods normally set at 7 feet from the floor require well over 8 ft ceilings. How high was your hood again, @opaone? And how high is your kitchen ceiling at that location?

P.S. To avoid future confusion, please note that Prestige in their specification uses capture area to mean the area of the baffles. In all my usages on this forum I use the open area flush with the bottom of the hood as the capture area.

@kaseki -- "spouse head bumping test" -- hah. But In my case I have 30" range and uppers on either side with 36", so I could only overlap by 3". Even doing that seemed nonstandard when I asked my kitchen designer/cabinet maker to do it, so it seems these things are really not well-known -- I wish I had deep dived properly into the detailed ventilation discussions you and @opaone have written before doing the kitchen reno, but at least we did put in the extra 6" width. Similarly re overall requirements you've written about in the past, I don't have a make-up air setup or strategy (though I do have many windows nearby including one exactly opposite the range) because once again, until I read all the content here recently on it nobody (contractors, etc) ever mentioned this is something we should be thinking about.

Good tip re Wolf outdoor-oriented product as another option, would have to look into whether there are installation spec requirements, even if they're not important from a technical perspective, that might pose a problem with using something like that indoors first (home insurance implications etc).

@opaone I see the class E.1 FAQ update, thanks for the shoutout! -- though I think @gardengrl66 z5 should get original finders credit for highlighting the somewhat undiscussed brand. I wonder if the 30" High Capacity hood is actually a new product and that's why there doesn't seem to be many reports about it yet?

Anyway @gardengrl66 z5 would definitely be interested whenever you have an update on what you end up going with -- it's likely going to take me a lot longer to figure out what to do myself (also there's a secondary issue which is that, based on a quick search, Prestige hoods don't seem available from Canadian appliance distributors)

@d7sharp9 thank you for graciously sharing credit. I am planning to get serious about tracking down that Prestige rep on Monday. Looking at an Electro industries makeup air system. Will keep you posted!

Here is the link to Wolf's Outdoor hood installation manual.

https://www.subzero-wolf.com/-/media/files/united-states/product-downloads/sub-zero-wolf/installation-guides/wolf/owhood-ig.pdf

Okay, excellent people...I am progressing on my hood choice and need the hive mind to weigh in on the blower situation. Please tell me if I should start a new thread, as this post is not completely about the hood. The update, is that I spoke with Prestige today and they have sent me a quote for a 40-inch "high capacity hood" (pic above on this thread), plus a wall switch (because the standard switch is up in the hood, and I would rather not reach up there to adjust while cooking is going on) and a quote for each of their in-line and external blowers, both 1000 cfm. Because of the large containment volume in the hood, there is not room for an internal blower. I am getting a nice discount if I order all of this from Prestige (as opposed to, say, getting a blower from Broan or Fantech)

So, here is my setup: Cooktop is going on an outside wall, single story house with 8 ft ceilings. I believe there are about 4 vertical feet of attic between ceiling and roof. I would like, to optimize the physics of it all, to just go straight up through to the roof. (It is a 10-inch duct looks like). And I probably am going to want a silencer, yes? which makes it doubtful that the inline blower is a candidate because there is probably not room for both in my attic, without introducing turns into the ductwork.

I am attaching the installation instructions for the external blower and this is my question: While the instructions do not state that the blower cannot be mounted on the roof, all the illustrations are about mounting it on the wall and nothing about roof mounting. I have never installed a vent system, and it is clear that my contractor, while very nice and probably perfectly competent, has never had a customer who wants this degree of ventilation. So, can anyone out there tell me whether there is any fatal detail in these instructions, that would make it impossible to mount on a roof? Thanks in advance!

-gardengrl66

Nice. Houzz ate my entire response and apparently flushed it.

Nice. Houzz ate my entire response and apparently flushed it.

Argh!!!

OP, the instructions don't seem to match the blower. If the blower is intended for roof mounting as they say then it should have a flange or curb attached and running around the entire unit. This flange is secured to the roof sheathing and then shingles overlap the flange which is what prevents water from getting inside. So long as it is manufactured correctly for roof mounting and has the flange then your HVAC folks shouldn't have any problems.

FWIW, I personally prefer an inline blower that can be in a attic or similar space, protected from weather and easy to access for cleaning/repair. It looks like their only option for that is 600 CFM though. OTOH, I think @kaseki has an external blower that has worked well.

In addition, part of what I was trying to write was: the 10-inch Fantech silencer is three feet long, so fitting it between a roof blower and a ceiling only 4 feet lower may be difficult. Instead bend the ducting toward the inner attic at some angle, install the silencer, then connect the remaining ducting via a pair of bends to a the blower mounted where all this will work. (Recursive layout warning.) Easy bends will add pressure loss, but I think your baffles will have higher loss.

Also, get dampers as required from Fantech or other sources.

Get band clamp type connectors for the silencer from Fantech.

Hang the ducting and silencer as may be possible from the rafters using flexible straps.

It may be possible to build a roof pedestal that adapts the Prestige blower to the roof angle such that it meets its pitch requirement (whatever that is) and is adapted to the shingles via a proper flange. Wolf, Broan, and Abbaka make fully compatible down-roof centrifugal blowers. (IIRC, Abbaka on-line literature has good illustrations.)

Last, unless you have worked with 10-inch duct, it will amaze you with how much space it takes up. So plan accordingly.

Thanks to you both for responding. @opaone, I think I did not express myself well; it is I who want the blower on the roof rather than the wall. These instructions only describe how to put it on the wall; your comments about what should be included, make me suspicious that this blower is only designed for wall and not roof, which means I should probably look elsewhere if I'm wanting an external blower. That would probably be easier than @kaseki's suggestion to have someone build an angle-adjusting pedestal for the Prestige blower! (that rustling sound you hear is the greenbacks going for extra labor and material costs...)

And I am certainly missing something, but crawling around in an attic to clean a blower sounds much less pleasant than tackling one that is on the roof! (Remember I have a single-story house so not too death-defyingly high) The thought of being in my attic for a prolonged period really triggers my arachnophobia.

and Kaseki thanks for the how-to on setting up a silencer. Nice to hear that some not-too-acute bends in ducting will not make a material difference; I've sort of gotten the vibe from the FAQ threads and others, that bends in ducts are to be avoided! Yes, the attic is taller towards the center of the house.

I will look at the Wolf/Broan/Abbaka blowers...

Bends in ducts correspond to a lot of feet of straight duct (varies with angle), but pressure loss across the baffles is also worth a lot of feet of duct. For example, using data I got from Wolf about 13 years ago, the Broan-NuTone 801641 on high with some unspecified hood and duct size, but presumably appropriate or they wouldn't have developed the resistance curves to apply to the fan curve, the effect of adding 100 ft of duct is a flow rate loss about equal to the amount of flow rate loss due to the hood with zero feet of duct. At a constant flow rate, the effect of the baffles is equivalent to 75 ft of duct. So for many systems, the baffles dominate unless the MUA is too restrictive.

opaone - Did you ever consider a 36" deep hood? A 60" x 36" ? Wouldn't that be the most effective? As opposed to having Accurex custom build you a 60" x 30" hood? By default, their hoods are 36" deep.

We did consider it. Personally I think I would have been fine with it. My wife, interior designers and architects thought it would stick out too much so 30" was kind of a compromise and I think the cost was only about $200 more.

I don't think we lost much in functionality vs 36" and what we have still works much better than any consumer hood and is much quieter.

opaone - Did Accurex try selling you the make-up air that's connected directly in front of their hoods? From my research, some commercial kitchens connect it to the front of the hood to create a "curtain" of air down the front edge of the hood, above where you stand, with the purpose of helping to push the cooking smoke back up to the exhaust. I've tried to do some research on this but I'm having trouble getting a consensus about its effectiveness.

I checked out your website (beautifully written by the way) and it seems you opted not to go that route. What are your thoughts on makeup air and where to place it?

I think going with the 30" depth hood worked out great for you.

The enemy of good capture is turbulence in the volume between the cooktop and the hood. Air curtains are not very good at avoiding this when there is an actual cook being blown upon. (If unheated, the cook might not like it either.) Many commercial rigs introduce the MUA at the hood, but direct it across the room where it can diffuse, curl back and approach the cooking area at a slower speed with quasi laminar flow behavior. Accurex should be your source for discussing advantages and disadvantages of their systems.

More details about air curtains and such can be found in various California Air Resources Board (CARB) publications related to commercial kitchen ventilation. I think the topic might also be addressed in the Greenheck guide, available at: https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf.

@gardengrl66 did you end up installing the Prestige high capacity hood/insert? Which blower and MUA did you end up selecting? Are you happy with their performance?

I'm on a similar (right down to the inspiration photo!) search for a range hood and I'm running into the same challenges, with the added complication of being in Canada.

After being unconvinced by the VAH spiel at the appliance store and getting no response from Accurex, I decided to stop lurking and resurrect my old Gardenweb account. Your post has given me some hope!

Well. There is good and bad in everything, I suppose, so here's the rundown. I did install the Prestige and it looks and works great. The baffles are not too hard to take in and out, the lights are good, the venting is great. I've seared salmon and been unable to smell it across the room, and all the visible steam seems to be going up the vent and not spilling around.

I do wish there was a little bit more variation in the blower speed. High is great, low is really not that low. But I'll take it over any situation where "high" is not...high.

The really tough thing is that there is leaking somewhere along the line between the vent and the external, roof-mounted blower. When it is rainy and windy, or when snow is melting off the roof, I get water on my cooktop. My contractor has been up once to try and trouble-shoot - I am not certain exactly what he did but it didn't work. So make sure you have someone who knows what they are doing on the install. I have to keep in mind that no one in this small mountain town has really installed a range hood like this one, and hope eventually to get the thing to be waterproof.

I chose the MUA system from Electro industries because it would fit correctly in my attic. The air comes in through a pre-existing chimney opening (old wood-burning stove was there before), and thence into the utility closet and through a louvered door, all of which is way across the living space from the stove so it's nice, gentle air flow that doesn't blow the cooking fumes sideways. The problem here is also, I think, a side effect of living in a small town. No one on my team had even heard of MUA before, only in a commercial context, so I think there are problems with the wiring. It works for a day or two, and then won't turn on. I've been through three rounds of this, they go up and re-set a bunch of things, it works, they go away and then within a week it is not working again. Very frustrating.

But boy when it works it is great. If you have good installers I would recommend the unit absolutely.

Hope that helps! And if anyone on the thread has any constructive advice on my two issues (roof leak, mystery cause of MUA not to turn on) I would greatly appreciate it!

-gg

Perhaps the manufacturer and model of the roof blower, along with the slope of the roof, and perhaps a [tele]photo of the blower would help us guess.

It's an RB 1000 by Prestige. I'll try to get a picture of it on the roof later today...thanks

Thank you for the update, @gardengrl66! I've been quite disillusioned in my range hood search but you have reenergized me somewhat. Your setup with the MUA coming through the utility closet sounds perfect.

How do you find the hood's noise level?

I'm sorry to hear of the issues you're having--it's always a bit more of a challenge doing something no one else in the area has done before. I hope things get sorted out quickly so you can really enjoy your new kitchen!

prestige RB 1000 is only 6 inches high, and doesn't have a moveable damper on the output side (as Wolf/Broan) roof blowers do. It might be possible to flood this unit, depending on roof slope. I would look at the interface between what looks like a duct in their image and the sheet metal that is interleaved with the shingles (which looks too small in their photo).

Thanks this is timely as we just pulled in to the house after a few days away. There was snowfall and the leak is much worse. Standing water on the floor around the cooktop even. Here is a pic of the unit on the roof

Thanks this is timely as we just pulled in to the house after a few days away. There was snowfall and the leak is much worse. Standing water on the floor around the cooktop even. Here is a pic of the unit on the roof

Sorry about the duplicate text!

Slope looks reasonable to me. So all the paths around the unit, as well as into the unit, need to be checked for adequate sealing. If necessary, get some respectable roofing guys to pull the blower and replace it while establishing an adequate seal to the roof. They won't do any internal sealing, so that needs to be looked at.

Alternatively, the entire unit could be put onto a pedestal tailored for your roof slope so water doesn't flow around (and through) it.

Have you looked into the attic to see where the wettest spots are on the roof wood close to the blower?

Update - according to my GC all is well-sealed, in fact he has said it will take "significant effort" to pull the blower. A process, I gather, involving a heat gun to soften up all the silicone. Nothing is really wet in the attic, the water just seems to be coming down the actual ventilation duct. I am really surprised this has not been previously recognized as a design flaw for this particular blower going up on the roof!? Surely there's enough rain and snow in communities everywhere that this problem would have been discovered?

We discussed the pedestal idea - he can build one up to 12" in height (that is the widest that the wood comes in, beyond that it's more involved) - but this wouldn't be 100% protective as sometimes we get more snow than that, and it was a big snowstorm that led to the recent flooding onto my cooktop and cabinet.

He proposes to re-route the thing out through the side wall of the house. I'm inclined to agree, just to get things going before the next spring snow hits...

Blower pedestals, also called roof curbs, are typically metal, and made by a sheet metal shop or blower manufacturer. Dimensions are parameters to be specified if one needs a custom model. (See, for example, https://www.fastcurbs.com/Pitched-Curbs)

Alternatively, if multi-foot blizzard dumps are an issue, one can use an in-line blower and a tall duct with a cap.

'Side-of-the-house' is certainly a solution that might be the easiest to address.