@M: If your configuration noise problem is merely having to have a short duct run to the outside, it is always possible at some cost to adapt the exterior interface to an 'oversized' blower -- possibly commercial style -- operated over a lower-than-full-speed range. If I correctly recall the material above, @opaone has an underspeed blower setup for low noise.

Yes, in most cases that would be possible. Our situation is rather unusual. The kitchen is on the top floor of a house built into a hill. The flat roof is slanted and there really is only one direction the ducts can legally run. In that direction, we can't vent to the side of the house as that wall is pretty much inaccessible because of the hill. But the roof has a deck on top that limits where to even put the vent to pretty much a single possible location. And building codes prevent us from building anything tall in that place.

We're quite literally between a rock and a hard place. I'm so happy my contractors found even one location to squeeze things into. A big external blower just won't work.

Sometimes you're forced to work within the existing conditions. I certainly would do things differently if I had built the house from scratch. But that's all hypothetical at this point.

Thank you @Elmer J Fudd. For better or worse I've lived with these things for several decades and have sort of learned to manage.

To your points...

First, there are much more important things to worry about than if someone is crowing about wood floors or whatever. In the U.S. we have the lowest life expectancy of all developed countries and the highest rates of preventible diseases as well as poor (and declining) academic performance. Poor indoor air quality in our homes, including new homes currently being built, is one component of our poor health, early death and poor academic performance. Helping people to understand that and what to do about it is far more important.

So...

separate furnace for make up air (really?) - Yes really. It is standard for commercial systems like ours including when these systems are installed in a residence. And not a bad idea for many people installing consumer hoods. In hindsight I now wish that we had done it. The cost would have been about $1500 for a gas fired furnace for our MUA and would have allowed us to put the MUA vents exactly where we want this air to be introduced - in the opposite side of the kitchen from our range. It also would have saved on the cost of pre-heating the air w/ electricity which is currently done by the MUA's. A better option that I wish I'd thought of sooner and that @kaseki mentioned is a hydronic duct heater. We already have a large boiler so this would have been even less expensive to install.

the type of wood used for the floor in the kitchen, the backsplash and counter materials - If you look at the top of this thread you'll note that it is posted not just in HVAC but also in 'Appliances' and 'Kitchens'. So yeah, those topics are relevant and perhaps interesting for some. AND, I (and presumably others) learned something about white oak that I didn't know before.

And I'm totally befuddled how this could be considered crowing when these are common materials that a gob of people on these forums use frequently. If we'd used something exotic then perhaps but we didn't and we actually spent less on materials for our kitchen than many. Interestingly, the hood is a good example - ours is simple painted wood box, no copper or brass or iron or flairs or chimneys or anything. Our hood surround is probably one of the simplest on Houzz.

dinner parties for 40 with hired help causing air turbulence in the kitchen - Quite often those 40 people are my wife's six brothers & sisters, their spouses, their children (13 nieces & 1 nephew), spouses, boyfriends and a girlfriend and now their children. Often plus a handful of extraneous friends, visiting missionaries or someone from my side of the family who have decided to brave the elements and come up here from Alabama. These gatherings are often pot-luck kind of affairs with various people bringing things and many of them in the kitchen at the same time either preparing something they brought or hanging out and chatting. And it's crowded and chaotic and quite wonderful.

And, that air turbulence is actually an issue and one that would have benefited greatly from... a separate furnace for MUA that would have allowed us to introduce MUA to the room on the opposite side from the range creating much better airflow in the kitchen.

My frame of reference is that I live in an area where over the last 50 years having the right idea at the right time produces megawealth (the examples are well known). Getting less attention are the many, many thousands who, having the good fortune or good timing to become associated with such companies at the right time, were able to make $50 or $100 or $200 million and more.. And others in support roles who have also made big bucks. Not megawealth, but certainly very substantial wealth. I've known many such people over the years.

When in mixed company (that is to say, with people of more modest means), their interests, spending and experiences such may bring, are never mentioned but if so, only with modestly.. Someone may mention going skiing in Aspen without saying they flew by a private jet charter to their $5 million lodge. Or spent two weeks in Tuscany without including that while there, they spent $10 million for a stately old home set amid vineyards.

Do as you wish, I explained my thoughts .

I will admit I did not read every single word of this thread, but I am a professional mechanical HVAC engineer and design commerical kitchens all of the time, and will thrown in my 2 cents. Professional/commerical kitchen hoods are not required for residential kitchens. Residential hoods are designed for residential applications. Unless you are cooking with heavy duty commerical kitchen appliances, like fryers and what not, I would not recommend the commerical hood, mainly because the exhaust rates are much too high especially without a make up air system. Your home will be extremely negative if you do not have make up air, and your infiltration rates will be high, which can cause problems with capacity in your system because it is not designed for the higher loads. A furnace is not and cannot be a make up air unit. A make up air unit, direct or indirect fired, or hot water, takes 100 percent outdoor air, and is balanced to be slightly less than the exhaust. This is to keep the kitchen negative is relation to the other spaces to contain odors. A furnace has the ability to provide a small portion of outdoor air, but for the most part will just recirculate air. This does not fix the air balance issue. My advice to anyone considering this would be install a fan with an ECM motor so you can adjust it to your liking. Turn it up if containment is becoming an issue, and keep it lower for the majority of the time.

@Angela Bickford nice to have you aboard. Please note that the OP's (@opaone's) system was professionally designed and installed, and has a tuned make-up air system. While I too don't recall every word of this thread, I'm pretty sure that his result includes the ability to achieve equal or better capture and containment on less volumetric air flow than I require using Wolf's largest Pro Island hood. I believe that this is due to the larger reservoir of his hood providing plume averaging over the baffle surface area that a low volume reservoir hood cannot achieve without some spillage.

Hi @Angela Bickford. I don't disagree, including for ours. OTOH, it was one of the better decisions we made.

If you'll browse the Hood FAQ linked in the first post you'll understand a bit why. There is a huge gap in performance between consumer and commercial hoods. The best consumer hoods do not provide the effluent removal that we desired nor the quietness. Lacking a better option we went with the Accurex and are quite happy that we did. It provides:

- better performance than any consumer hood is able to provide,

- is quieter than any consumer hood,

- is up above our heads and totally out of the way and

- provides better lighting.

I'd do it again in a heartbeat. And the cost was not that much greater.

To your points:

"Residential hoods are designed for residential applications."

Not really. They are designed to appeal to consumers desires for marketing gimmicks. Many perform poorly and the rest are worse.

That said, some do OK. @kaseki's seems to do well for example and I know of other similar systems that do. OTOH, I've been in homes of people who've told me that their's works well and couldn't wait to escape the odors of meals past and stale grease wafting through their home and the noise of their hood.

"Unless you are cooking with heavy duty commercial kitchen appliances, like fryers and what not, I would not recommend the commercial hood, mainly because the exhaust rates are much too high especially without a make up air system."

The exhaust rates are actually not very different, you should know that. Our Accurex hood actually performs better at lower actual CFM's than a consumer hood because of the containment area - something else you should know if you are an HVAC engineer and especially if you design commercial kitchens.

Further, EVERY hood over 600 rated CFM's whether consumer or commercial requires MUA. Again, something that you should know.

"My advice to anyone considering this would be install a fan with an ECM motor so you can adjust it to your liking. Turn it up if containment is becoming an issue, and keep it lower for the majority of the time."

CFM's cannot make up for lack of containment - again something that you should know. A lot of cooking techniques such as pan frying are extremely bursty which is why commercial hoods all have such large containment volume. The large containment volume contains the bursts and evens them out so that the exhaust works more efficiently at lower CFM's.

Really? Trashing the opinion of a professional mechanical engineer who works in the field?

First, nobody is trashing anyone or their opinion.

Second, engineers are not gods. I've hired and fired them and I've disagreed with them thousands of times. In this instance in particular she implied that consumer hoods do not need MUA which is a dangerous thing to say, particularly if she's a professional engineer.

If you have issues with the technical aspects of what I wrote then put it forth, otherwise please stop harassing me.

Why bother hiring advisers if you question their ability and fire them when they disagree with you.

?!? Where do you read that @opaone fires people when they disagree with him? That's a gross misrepresentation of what he said. His statement was a lot more nuanced.

And incidentally, I agree with that statement. As a first approximation, it probably is fair to assume that professionals know their own subject matter much better than the home owner. But these questions are so complex, nobody can give perfect advice every single time.

I can't count the times that contractors have told me that they want to pick either my brain or the brain of some other contractor to figure out details that they are not comfortable with themselves. It's a team effort. Nobody can be expected to do it all alone, and sometimes a home owner has a lot more time spending months on end researching a topic that a professional simply cannot afford to work on. There is no shame in that.

In the reverse is true as well. Quite often, the home owner simply didn't go into enough detail and the contractor's experience wins out.

In my experience, neither expert advisers nor someone like a general contractor would ever ask for advice from or consult with a customer/client without a relevant background (besides being the one approving or paying the bill) concerning any technical subject matter that's the professional's stock in trade. They might double check requirements and expectations, or ask about what's needed if they encounter something unexpected or they find they want/need a little wiggle room, but not beyond that. Someone who thought they were so consulted is either fooling themself or was dealing with an adviser of less than stellar competence.

"Perfect advice" doesn't exist, not in any field. Nor is it ever a goal. I was a professional adviser, an expert in my field. Any client who tried to tell me how to do my job or second guessed my advice (technically) would find I played a "one strike and you're out" game. You could ask me to explain my advice or why I chose what I chose but suggesting alternatives to me was out of bounds. The onoy exception was for very large, ongoing clients that were a continuing source of a lot of work. Their continued patronage and loyalty bought more patience. We resigned from clients and walked away from work all the time for those who were too high maintenance or made it needlessly hard for us and our staff to help them.

Except for those with a shortage of work, I think my attitude in this regard is common. Finish the job as best you can, consider it the last job, and for any referrals from that person/company, it's "sorry, I really don't have time to help you".

That's why I had the thoughts that I've described.

Not sure what you thought you were reading in my post, but I said that make-up air is most definitely required, especially at the airflow levels you were talking about. The main difference is that commercial are kitchens are operating continuously, not for an hour or so here or there like a residential kitchen typically is. An occasional air balance discrepancy is not as critical as a constant one.

Exhaust rates are most certainly different for the type of cooking appliance under the hood. Please refer IMC 2018 507.

I am not disagreeing with the system you installed. Quite the opposite, you did your research, and you have enough information to be dangerous. I believe your system probably works great, is slightly over-designed, but generally works how you intended it to. My advice was for the general consumer who does moderate cooking. Of course there will be some residential systems that perform better than others. My point in writing the post is that if the general consumer takes your advice, but picks and chooses parts of it without an actual engineered design, it will do more harm than good.

I understand containment, and many other concepts surrounding proper commercial kitchen ventilation that are not even mentioned here. HVAC engineering in general is more of an art than exact science. There are many variables to take into account and the solutions are typically a balancing act of trying to solve what you want to accomplish vs. mitigating the negative effects.

@Angela Bickford: Practically no one visiting this forum with kitchen ventilation questions is directed toward this thread for the purpose of suggesting acquisition of a commercial system. The only case I can recall is someone who wanted a char broiler in his cooktop. Rather it is intended to showcase the project scope and resulting performance of adopting a commercial approach to a residential requirement. It may enforce reality onto those who want a vent at 7 or 8 feet above the floor.

It also conveniently illustrates an issue that is important for residential hood configurations: Low reservoir volume below the baffles limits plume averaging at the baffles and forces higher air velocities at the hood capture entry point than deep, high reservoir, commercial style hoods require for operation with only a portion of the available burners producing high velocity (ca. 1 m/s) plumes. @opaone has demonstrated this to my satisfaction.

Most visitors are given suggestions relevant to residential oriented hardware, and pointers to threads such as this as well as the Greenheck Guide for appreciation of the concepts underlying cooking ventilation. We also have a running thread with aspects relevant to its title: Hood FAQ. This is residentially oriented, but desperately in need of editing.

We also appreciate the need for MUA that is house pressure controlled rather than tuned to a particular hood running continuously. Houses after all usually have a few exhaust vents, the hood itself is run at variable flow rate depending on the cooking, and windows and other leaks are varied and variable. Passive and active (blower) schemes are needed depending on maximum allowed combustion appliance back-draft house pressures.

And yes, trades are needed in design and parts selection just as they are in most other engineering fields. No matter how elaborate the process, ultimately the tools that yield claims of optimality can be perverted by trade weighting to yield almost any answer. Hence, all the stakeholders need to be involved. In the residential kitchen, these include the homeowners, who have cost and aesthetics veto, as well as some preferences (perhaps naive when they first arrive here) about performance. We try our best. Feel free to tour various hood and MUA threads here for insight into the suggestion space we occupy. Also feel free to put in your oar. It is easy for even experts, not to mention informed amateurs, to overlook something. (One only need review the history of systems engineering on the F-35 -- starting with the Government's plan to use a single airframe for three Services -- to see how a very complex system of systems can embed multiple, er, errors and omissions of judgment.)

"HVAC engineering in general is more of an art than exact science."

This comment of Ms. Bickford is true of most professional practices.

Knowledge and experience provide a basis for professional assessments and decisions, the dark art she mentions that outsiders often don't understand or get the flow of. It's precisely why and where self-appointed experts, to use another of her phrases, "have enough information to be dangerous" because the second part of the task, applying judgements and fabricating a knowledge-based solution, is beyond the ability of an amateur.

All are welcome to their own opinions.

Thank you @Angela Bickford and @kaseki for focusing on substance. I find this thread valuable to the degree that it discusses practical matters in terms of ventilation. I suspect that most readers of the thread are, like me, not planning to put in a commercial venting system - but that doesn't mean we can't learn by reading about someone's experience doing such a thing.

Thanks Elmer. You hit the nail on the head. Solutions start with the basics of the concepts, and then evolve based on past experiences and applying your engineering judgment. There are hundreds of times where things do not behave like you think they should, and there is a variable impacting performance that takes a while to figure out. It's a lot of tweaking to get things perfect.

This comment of Ms. Bickford is true of most professional practices.

Knowledge and experience provide a basis for professional assessments

This cuts both ways. Experience is incredibly crucial as a tool to weigh trade-offs. But it can also fall flat.

I can't comment on HVAC questions, as I am at best a curious lay person. But I have had a related experience with electrical work on our house, where we were able to put together our different skill sets quite nicely.

I love my electrician. His workmanship is unrivaled. He knows the code front-to-back, back-to-front, and sideways. He knows where to find relevant engineering tables and he knows how to read them. And he certainly has done his share of both residential and commercial work.

Having said that, he couldn't read electrical schematics or answer basic electrical engineering questions if his life depended on it. Even his ability to extract information from data sheets leaves quite a bit to be desired. This all works fine until he runs into a non-standard construction situation, where the architect can't spell out every single detail as the manufacturer hasn't provided complete documentation. And our decision to put commercial lighting fixtures into a residential installation is decidedly non-standard.

In this situation, reading between the lines, making educated guesses from partial information, and future proofing by allowing for multiple options are all important. My electrician very humbly admitted that he does not have the training to do any of this, but he'd be happy to implement whatever I recommend. I spent a few hours doing some research and some back of the envelope calculations and told him which wires to run. Turns out, that was exactly what we needed and by the time the fixtures arrived we had all the correct wires in the walls.

As I said, it's a team effort and different team members have different skills. I can't do any of the code compliance work. But I certainly know Ohm's law (and a lot of others).

When I said professional opinion, I meant an engineer, not a tradesman. That's not to say that there's anything wrong with one or the other. I work with mechanical contractors all the time, but we are two very different occupations. There's things I can do that they can't and vice versa.

Honestly, I would be pretty wary to use the electrician you just described.

You're describing a very sub-par electrician. He's a worker-bee, needs to be told what to do. Reading schematics, data sheets, answering questions, are BASIC, BASIC, BASIC. Why hire a tradesman like that lacking skills typical of the trade? I hope you weren't paying standard rates for a hack like that.

An amateur (the customer) lacking training trying to digest something they have no background or experience with cannot make educated guesses. Just guesses of the wild-axx type.

Depends on how easily one can learn new things. Try avoiding assuming, Elmer, that everyone in whatever basket you have assigned them to is identical. Further, my guess would be that the NFPA would take exception to your "sub-par" assertion.

Now that we are back on track, I'll give my 2 cents.

@opaone, I think posting a thread about your journey to install a commercial venting system in your house is harmless, but I have to agree whole heartedly with the professionals here it just wasn't necessary. Not everything in life needs to be necessary to take enjoyment though, I get that.

Forget the math and the theory behind what you are trying to accomplish for a second. I have a 1400cfm residential ventilation system with makeup air that I designed and installed myself 3 years ago over a 48" range. I have modified bluestar burners that are putting out just shy of 30k btu for each of the front 4 burners. I deep fry, I wok fry, I cook daily. I use a technique I like to call "dry smoke" cooking where I fry veggies and meats in a wok with just enough oil to get the wok billowing with smoke. It adds a char flavor to my dishes but as you would imagine places a huge demand on the venting system. I've worked in restaurants years ago, I promise you it is near impossible to put more demand on a venting system than I do. Adding to all that, I have an unsealed brick backsplash that butts right up against the range.

3 years later, I do not have one drop of oil on that backsplash or build up of any kind. I've literally not cleaned it in 3 years. I can cook with any technique I want and nobody can smell what I'm cooking. I have zero grease build up anywhere, heck 3 years later and I have yet to wipe down the upper cabinets that sit right next to the range on the sides. On top of that, my system is quiet. Like I said forget the math and theory for a moment, my kitchen is proof residential ventilation can work in the most demanding of situations. I am happy to share further details of my setup if you are curious.

@catinthehat ugh your kitchen sounds like a dream. Glad you haven't had any issues with your ventilation!

@Angela Bickford Thank you! I am actually very proud of it, but as a civil engineer it did take me quite a bit of research to understand what needed to be done.

@Angela Bickford and @catinthehat, can you tell me what specifically is different about my system vs a consumer system that would be recommended for our same range/application?

And also, more specifically what about my system causes you to say:

"Professional/commerical kitchen hoods are not required for residential kitchens. Residential hoods are designed for residential applications. Unless you are cooking with heavy duty commerical kitchen appliances, like fryers and what not, I would not recommend the commerical hood, mainly because the exhaust rates are much too high especially without a make up air system."

"is slightly over-designed"

"I have to agree whole heartedly with the professionals here it just wasn't necessary"

Thanks,

@catinthehat I would be interested to hear details of your system - maybe in a new thread?

"I would not recommend the commercial hood, mainly because the exhaust rates are much too high especially without a make up air system."

I let this slide before, but it needs to be corrected for thread and FAQ consistency. If there is no adequate source of MUA, the exhaust rate will be too low. Perhaps what was meant was that a very powerful high flow rate at zero static pressure blower would be needed if MUA were limited to leakage paths. This would, however, be unsafe if any combustion appliances are in use in the residence that don't have their own MUA sources.

"is slightly over-designed"

I would also assert that one man's "over-designed" is another man's provisioning for margin.

Hood system apparent "over-design" can be a means of reducing noise.

As someone who has designed and installed commercial kitchen hood systems for 20 years I have a couple thoughts on this. You have done your home work and your system has solid engineering. Accurex is one of my favorites to work with.

The one thing I can not get past though is you have a commercial hood system with residential duct. The big red flag is the silencer. NOBODY should put a silencer in a potential grease laden system. Its a huge fire hazard. A silencer is nothing more than a dual wall duct with insulation sandwiched between. The interior liner is perforated metal with exposed insulation to absorb sound. That perforation and insulation will hold grease especially at the rate you are exhausting. . Even with your baffles you will get grease past them. Commercial equipment should be installed to commercial standards and this is not. Be careful please and have it professionally cleaned often.

@opaone out of respect for your thread and what you’ve accomplished I’ll start another thread on my own system to help anyone who is curious, although to be honest I really didn’t reinvent the wheel, minus a few (creative to me) solutions for my particular setup.

My hood isn’t commercial sized so I don’t need a commercial sized blower requiring a commercial sized MUA unit, ducting etc etc. In this case a “slight overdesign” actually results in quite a jump in expense.

I believe that controlling air flow around the cooking area is far more important. Where in a commercial setting you may not have much control over that, I went to great lengths in my house to make sure there is zero cross breeze or air disturbance of any kind around my hood, and I designed my MUA so fresh air is provided adjacent and below my range to encourage upward migration of the plume. I actually have a MUA blower, damper, and ducting network under my house for this. Consequently all my cooking plumes go straight up, there is no expansion like you see in serveral or those pictures floating around showing how a plume with grease and smoke expands. Sorry if this contradicts some of the literature out there but I literally can see it with my eyes.

Again I’m not saying your choice was a poor design. Your thread is a fantastic read. I’m saying there’s more than one way to achieve the levels of containment you seek, and unless you have two side by side 60 inch ranges I am a firm believer that you can end up with a highly functional, quiet setup with residential equipment.

@Gary agree with your observation based on my admittedly limited experience. My own 1400cfm blower is externally mounted 14 feet up the side of an exterior wall with a 20 ft equivalent length duct run from the hood. Well one day I glance up there and notice huge streaks of grease splatter on the side of my house coming from the blower. I cook enough that if I don’t remove and clean my baffles every 2 to 3 weeks they will start dripping grease. I‘ve since installed a deflector plate for the grease but I’m scared to think what the inside of that duct looks like.

@Gary: I have both an 8-inch and 10-inch Fantech silencer and neither showed any sign of internal insulation when examined from the ends. There is a perforated duct diameter inner cylinder and an outer cylinder (duct diameter + 4 inches in the case of the 10-inch size). Nothing insulation-like was visible in or beyond the perforations, although I didn't test by probing.

I have assumed that interference between the sound propagated directly through the silencer inner duct and the sound pressure waves that are leaked into the chamber and back with variable delay provides the high frequency sound level dampening. (These silencers do not attenuate low frequency noise.)

You are correct that use of naked insulation with grease would be a bad idea given the reality of the grease particle spectrum being only partially intercepted by the baffles. If you have further information on Fantech's silencer construction, please provide it.

@kaseki I have never seen a silencer that does not have fiberglass insulation. That’s what absorbs the sound. It’s 2” insulation according to this which gives you the 4” outer diameter you mentioned. silencers are great but should not be in a hood system

All these times I've looked up the parts and checked dimensions for comments here I haven't noticed that bullet. Maybe I've landed on a different page. Anyway, thanks. I should note that unlike presumably many here, our cooking has historically tended to cause a varnish like glaze of hardened oil on duct surfaces that seems to remain very thin. I will definitely have to inspect our larger silencer. (The smaller is adapted to a ceiling vent prefiltered with a furnace filter; negligible grease gets into the ducting.)

P.S. From Fantech literature: "Galvanized steel silencer for use in kitchen range hood ventilation and other applications where noise is a concern." Fantech's website also shows them in various hood related diagrams. I wonder what assumptions they are making and whether grease collection in practice is minimal for some (perhaps aerodynamic flow over perforations) reason, or just in practice in residential use.

P.P.S. It has occurred to me since writing the above that the fire hazard aspect might be ameliorated by the perforations themselves. Just like baffles and mesh filters provide the required fire barrier between cooktop and ducting, so might the perforations provide a barrier to flame propagation into the insulation layer. Dense insulation containing grease might itself not be able to support a flame due to lack of oxygen flow.

That’s interesting that fan tech recommends them for a hood. In most residential applications it may not be a concern. Most residential applications are a type 2 hood and a silencer would be fine. The original author no doubt has installed a type 1 hood with type 2 duct operating at type 1 capacity 1400cfm. In a type 1 installation all the duct has to be welded 16ga black iron or stainless steel. Must be welded liquid tight and sloped back to the hood with absolutely no dampers or obstructions inside the duct. .

Most residential applications have hood filters for grease and would qualify as Type 1 based on definition (although the type classification is not usually applied to residential systems). See Greenheck 'Guide' page 4. Type 2 are condensate hoods for moisture and odor and have no filters. See Greenheck 'Guide' page 7.

https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf

I disagree completely. Residential hoods are not type 1. Filters do not make it a type 1. welded duct, fire rated enclosure and up blast roof fans make a type 1 system. I’ll stick with my explanation that residential is closer to a type 2. Odor is 99% of what you are removing over a residential appliance.

Odor is certainly important, but keeping grease off the walls is also important, for most. Anyway, this is a digression. I have asked Fantech for a statement about fire hazard, or not, relative to kitchen hood exhaust system use of their silencers. If I receive an answer I will put it up here forthwith.

On this latter topic I think @kaseki and @Gary are both largely correct. Most residential cooking does not produce the amount of grease that commercial cooking does. This mostly because of lower volume of product produced - a commercial kitchen may pan fry 80 cuts of meat + veggies on a 30" range 6 nights per week. I may do that much once per year and half that 3 times on a 48". Cooking style also varies, though for example pan frying a single item is largely the same with the same effluent whether done on a commercial range or consumer though the higher BTU's of the commercial may produce very slightly more effluent both in gas combustion and in cooking.

As I said in the Hood FAQ: https://www.gardenweb.com/discussions/5161173/hood-faq

"For us our primary concern is our health and getting rid of the by-products of gas combustion. Second is reducing cooking odors as much as possible for ourselves and when we have guests. Third is reducing the heat in our kitchen when doing a lot of cooking and Fourth is reducing grease build-up on kitchen surfaces."

So grease build-up was a low priority and I actually left out one very important element - low noise.

We did have some grease build up around our former kitchen w/ our VAH (that was wider than our range and w/ proper ducting and MUA and cleaned frequently so should have been performing as well as it was supposed to). Because of how loud it was we didn't use it as often as we should but we did the majority of the time and always when producing more odor or grease laden effluent.

SO, I'm hoping and expecting that we will experience less grease build up on surfaces in our new kitchen with our new exhaust systems.

I do not expect to have grease problems w/ our silencer nor did the Accurex engineers believe it would be a problem though they did suggest inspecting it occasionally which we'll do. Also consider that the vast majority of the air flow through it is straight through unlike a baffle filter or blower. So there may be some minimal build-up on the downstream edges of the holes but likely not enough to be an issue.

As of the time this writing Fantech has not bothered to send a reply to my message requesting a statement on fire hazards. I believe I used a typical web customer communication form with some hope, but I have believed for many years that those messages are reviewed intermittently and then sent to the great bit bucket in the sky. So someone inquiring about purchase by telephone may be a better response.

The original author no doubt has installed a type 1 hood with type 2 duct operating at type 1 capacity 1400cfm.

Yes. I don't need full on commercial type 1. Per above we will not produce the amount of grease or smoke that requires a full type 1 system. HOWEVER, we like most residential, do need more than Type 2. We do produce some grease and smoke and some kind of baffle/filter is needed (or at least highly beneficial). The amount of stuff that I cleaned off our VAH and our current Accurex is a testament to that. So residential is perhaps realistically Type 1a (moderately heavy grease/smoke) and Type 1b (light grease/smoke) that are both less stringent requirements than full Type 1 (very heavy grease/smoke).

Our need/desire for a commercial hood though had nothing to do with that but rather containment. Consumer hoods all have inadequate containment volume (as well as inadequate capture area). So really the only thing about this system that is 'commercial' is that I have a bigger empty box.

We actually looked at using something like a Wolf and adding a 14" extension to the bottom of it to effectively increase its containment volume but in the end the cost to just have Accurex build a proper hood wasn't that much more expensive.

That was my issue w/ the ignorance displayed by @Angela Bickford on numerous levels. A bigger empty box like ours does not create a need for greater MUA or greater exhaust CFM's but actually quite the opposite as having proper containment results in much better effectiveness with lower CFM's (which is what is really bad about consumer hoods not simply having proper containment volume).

@catinthehat, as well as many others, actually have more rated CFM's than we do. Though we have a '1400 CFM blower' it is only used at 84% max or 1200 CFM but the larger blower is quieter at lower speeds and that is something that Accurex and CaptiveAire both do routinely to help reduce noise.

@opaone I have a question regarding your Accurex hood and the wood facade you had installed around it. I just had a hood quoted for a smaller size but one of the comments he had made was that because of the smaller width (30" instead of 36") that it would not be UL listed. Also because of the smaller width, it would not be insulated for clearance to combustibles, so in a commercial application the wood facade would not be allowed. He was not familiar with residential code and referred me to speak with the inspector. So I was wondering if you ran into any issues or if I am missing something.

Also, I may have missed this but what was your reasoning for going with the x-tractor filters over the normal baffle filters?

Ours is UL listed but I'm not sure that's really an issue for the hood itself though even if it were not. The blower should likely be UL however. Ours is also rated and labeled for 0 clearance to combustibles on all sides.

On the filters we simply went with what the engineer recommended. I believe her reasoning was that the x-tractor can operate at a lower CFM (196 IIRC) but I'm not positive.

A FWIW, my wife thinks it's one of the better things we did in our house. It's worked extremely well.

@opaone Good to know! I can understand thinking it is one of the better things to do. At our previous house, we had a hood that was noisy at its highest settings which resulted in not using the hood as much as it should have been.

I was quoted Accurex XBEW 42x30 for cheaper than what a Wolf insert would cost. Knowing this, it sounds like a no brainer to move forward with a commercial option. Would you be willing to share which engineer you were working with? Might make it easier when working with my contact to have something to refer to.

If I am reading everything correctly from what all you have written down. It sounds like you went with a 60Lx30Wx32H Hood, 14" duct, 14" silencer(fantech) with an 18" inline blower. Do you have access to the blower if something were to happen in the future? I'm personally leaning towards an external blower since we will have a vaulted ceiling in the kitchen. Also, where did you end up having the MUA come in at in the kitchen? I'm trying to gather as much information as possible before talking with our builder and HVAC sub.

Thanks again for all the information you have posted, has been a huge help in getting this all sorted out.

The blower is installed behind a knee wall in our loft so we have access to it through a removable wall panel.

14" duct and 18" blower sounds correct.

MUA (electro-industries) enters the return duct for the HVAC that serves that end of the house. I'd like to have run dedicated ducts but that would have required conditioning (heat/cool/dehumidify) which was extra expense. AFTER we had it all done @kaseki (I believe) mentioned that we could have heated it fairly inexpensively off our boiler. Wish that'd been mentioned a few months earlier :-)

We're controlling it with our HA system (Control4). A button cycles through Lo/Med/Hi speeds and then there are also up/down arrows for finer adjustment if desired. The MUA is turned on to Lo/Med/Hi based on the output of the hood blower which works well.

Lights are direct wired to our central dimmer system.

Heh. One man's inexpensive ....

Well, if you have a hydronic heating system and can add a zone to the boiler, and perhaps depending on flow rate and head can increase your zone pump or overall multi-pump size, and plumb the way to the heat exchanger (itself only a few hundred $$$), and put in a pair of thermistor sensor/relays, one of which assures that the plumbing in the cold area does not get close to freezing, and the other sets the air temperature past the heat exchanger to whatever one wants (note on/off control and not proportional here), and wires them logically to the thermostat connection for the zone, then one has a possibly inexpensive air heater. Filtering and blower and blower controls not included.

Electric heating is easier to install in an MUA path, I think, but changes to one's electrical service or at least to a breaker box may be in order. Electric should be lower pressure loss.

Our MUA's all have electric heat but set to only about 38°f IIRC - warm enough to not have to worry about damaging the heat exchangers in our furnaces. We want to use electric ($$$$'s) only as much as necessary.

I have recently seen a couple of smaller gas fired in-line duct heaters that would have worked for us as well.

Does anyone know if @catinthehat made a post highlighting the referenced install? I am very interested in both cat's modification of his blue star burner to 30k as well as cat's hood setup. I have a 36" bluestar and my current VAH is completely overwhelmed. I sadly couldn't figure out how to message here on Houzz.

Our old VAH that came with the house was overwhelmed as well. I believe the main problem was the limited overhang. Looks pretty, but doesn't really work that well. We replaced it with a custom-made extra-deep (front-to-back) ModernAire. It's amazing. Zero cooking smells in our open-floorplan kitchen.

We don't have a 30kBTU burner, but I swapped out one of the 22kBTU burner heads, and replaced it with a 25kBTU model, and I then also upgraded the orifice. We now nominally should have about 27kBTU. It's noticeably more than 22kBTU, but not a life-altering difference. In other words, nice to have if the option is available, but you won't miss too much if you can't find the parts.

You might want to do a search on @catinthehat and troll through the hits for relevance. I recall a thread on burner modification by someone; I don't recall a description of "cat's" ventilation system, but could have forgotten it.