Have you ever turned on your vent at the old house and observed the smoke coming out of the pots below? Grease floats in the smoke. I heard that if you don't use a vent you have at least one stick of butter a year spread around your house.

How greasy do you want your new cabinets to be a year from now?

If you have a ceiling fan in the vicinity of your stove you can see how much grease and dirt will collect on the blades in a very short time. My hood has two very strong halogen lights and you can see,even on a low heat,grease being pulled into the filters that would go in and on everything in the kitchen area and probably eventually the whole house.

Okay everybody, go ahead and call me an idiot, but I did not put a vent over my new induction cooktop. It was a remodel of an old 1952 kitchen and where I ended up having to put the cooktop, I DID NOT want a hulking hood. I have rarely to never used vents in my three previous homes so why would I start now? Granted, it has always been just my hubby and me and I'm not a rip roaring cook. Seldom fry anything and I mean seldom as we might have bacon only twice a year. I never noticed any problems in my other homes so nixed the hood in this remodel.

That being said, if you have the electricity and the roof penetration already then you might really consider getting one. I did not have that. In fact, the poor little previous kitchen had this old timey fan mounted in the wall above the door. You pulled a cord to turn it on. My situation is a little different, too, because my induction cooktop is only about four feet from a wall full of old timey crank out windows. I figured if it got too bad, I would crank open one of those. The only thing that is different in this home from my others is that the ceiling is only eight feet. All the others were ten feet. This could prove to be a problem...guess time will tell.

Finally, like others have said, it doesn't matter that it is induction. You will still get similar "stuff" going on when you cook. Only you can make this decision and I hope I haven't confused you. Just wanted you to know there is ONE other person (idiot?) out there who went "hoodless." Unfortunately, I have not cooked very much in my kitchen yet, so can't tell you if I made the right decision for my situation or not.

Oh wait, one other thing. Consider resale if you think you might end up selling this home. Most people would want a hood. Sorry if someone mentioned this already as I did not read every post. In my situation, hubby and I hope to live in this lake home till the funeral home people come to get us. HA!

ok, thanks for the replies.
I think you guys won this battle.
I am going to put one in. Im going to get one off of ebay for around $500. Hopefully it works out.

jache723,

I'll admit that everything I wrote above was a bit confusing so I don't mind clinresga correcting and clarifying.

What I really meant to say, in other words, is more like this: People who aren't using fans when they could be, dislike the Noise and the View. If I guessed right about your not using any fan at all, it is Noise and Looks. Considering you aren't even using a vent fan today (which says you aren't grilling much today, and gives other hints about your cooking habits), and seeing that your new cooktop is induction, don't go overboard with CFMs when you finally decide to go for it. It IS good to have a hood and fan. (= "Nobody will tell you that a no hood solution ..." ) The shape and size of the sump is a separate concern, not directly linked or related to the power of the motor pulling air. They are two different things. A hidden motor = inline blower = quieter and probably better for you. Having no "sump" , no umbrella = not optimal, not at all. But these things do exist and are available to be bought as kitchen vent fans. Hardly anyone buys them.

--True, with a backdraft damper you won't have convection currents going up the vent.

David

Well I will admit with my last kit and this one I fell into the "must have" and I do use it. But I really laugh every time this subject comes up. We grew up loving smell of home cooking. No one had vents. Now we all spend a fortune to rid the house and I guess we have to justify it. I justify it today because though I still love the smell of cooking I no longer enjoy the lingering after dinner. Grease depends on your style of cooking. I had an inadequate JenAir for yrs. Noisy so I didn't use it. I can honestly say even the white ceiling above had no grease. Neither did my cabs. my only frying is occas stir fry. We do not eat much of anything greasy.

Pupwhipped- did you end up regretting not having a draft? I am going through this same issue where a down draft is going to cost a lot and my contractor has told me I do not need one.

Hi Lisa. WOW, rereading this old thread brings back some memories. I almost wonder if I was drunk while writing that original post cause there are tons of typos and mistakes. Yikes!

To answer your question, I don't regret not having a vent hood in this particular home. But as I mentioned before, my cooking is not very intense, so to speak. In seven years here I may have fried something or other maybe three times. The most that's coming out of my pots and pans is a little steam.

I recall having a problem only one time. We do all our grilling outside on a charcoal grill. But one cold winter night hubby refused to crank up the grill saying it was too cold and windy...we live on a lake. I was bound and determined to eat a steak that night so I decided to sear it on the stovetop and then finish it in the oven. I'd not really ever done this before so I think I got my searing a little too hot. Next thing I know the smoke alarms are going off in our house. Oooops! We started flinging doors open right and left. Ha!

Now, I as I think I mentioned earlier, this house is our last one. I'm not worried about resale cause I will be dead at that point. If you think you might sell your home in the future, then I would definitely try to have some kind of exhaust. The vast majority of people would not be happy without one. I do kinda wish I could have had the pop-up vent, but as I recall, that was not possible with my setup. My only option was the honking overhead vent hood. And I just knew I would hate the look every single day, and I would seldom even use it. But that's just me.

Good luck with your decision! Oh, and forget about what your contractor says. He's not gonna be cooking on YOUR stove. You decide what's the best for you and your family.

Thank you for your response! I wasn't sure that I would get one as that was so long ago!! I think we have decided to hold off at this point. We plan on living in the house for a really long time and do all our grilling outside and most of our frying in our electric skillet anyways. I did have the contractor leave the venting for the downdraft so that someday I could add it if needed. Thank you again! Enjoy your house on the lake :)

We are building a new house. My induction cooktop will be in an island in open floor plan. I would love to know if anyone has a recommendation for make and model of pop up vent. There is no plan for an overhead hood.

That's a real shame, because new construction is the perfect time to put in an island hood. Not so easy to put in after the fact, as many people stuck with downdrafts in older houses have learned the hard way.

Angie: this has been discussed at some length several times over the past couple of years here. If you are having trouble turning up threads with a search, try including the terms "telescoping vent" and "retractable vent" in your search string.

To make a gross summary of what my failing memory recalls, the gist of the telecsoping/pop-up vent discussions has been to get get the tallest pop-up you can afford. Steam, grease and etc. tend to rise, mostly. The lower your downdraft's intakes, the less they readily pick up odors, steam, etc. The taller they are, the better they work. I recall BSH (which includes Bosch, Gagenau and Thermador) making some 14" tall ones and I think both Miele and Kitchenaid/Whirlpool have some models that rise to 13½" as well. (Note that some of them may require larger than standard venting ducts, though. I think I recall a Dacor that went to something like 15" high and needed 10" diameter cucting.)

I believe that there were some that rose up even higher but cannot recall the brands.

I think the one shown in Imalm53's photos, above is a Bosch.

If you go to websites like Lowe's or AJ Madisons, they will have search filters that will allow you to narrow your search to taller units. (You have to search under "range hoods" even though downdrats are not what anybody would think of as a "hood.") Check the fine print though, because some manufacturers try to skew themselves into the searches by giving the height of the undercounter portions rather than the telescoping part.

If you find something that works, please post back because others have the same question you are asking.

Angie- this is what I would look at.

This Broan subsidiary Best Catura model appears interesting but isn't scheduled for release until January 2016. It raises 19".

http://www.prnewswire.com/news-releases/the-new-cattura-downdraft-from-best-melds-best-in-class-performance-with-sleek-design-300021762.html

Here's an installation video.

Even if you're not doing any serious cooking you will create effluent (fumes and grease) into the atmosphere. I guess it's your choice but I can't imagine cooking without a range hood over my stove, no matter what configuration of a range you have.....

Edit: I guess if your just boiling water and don't do any serious cooking then go for a no hood application....

Back to the 1930's!!! A bathroom vent in the kitchen ceiling! Of course, back then, the kitchen was in a tiny room at the back of the house with a solid door to help contain the stink.

I wouldn't suggest it. If you're the type who hates hates hates fans, and would rather live with the steam, smoke, aerosolized fat, and odors from a cooktop, there are actual cooking vents that you can install in the ceiling that handle some of it. Much better than a bathroom fan. Additionally, pop-ups don't work all that well, but they work better than nothing. If you want to vent, however, you can usually find a solution unless the only wall you have to vent out of is the front of an older co-op or condo. It all just depends on your priorities and how much you want a vent system that works well.

If one looks deeply into the cooking plume measurements literature, one may find that the primary difference between gas cooking and induction cooking is that for a given pan temperature, the gas cooking effluent plume rises at a modestly higher velocity than the induction-generated plume, due to the entrained hot gas combustion products rising along with the cooking products. This nominally requires modestly higher air flow velocity at the baffles for the same percentage containment by the hood. There will also be differences in the plume divergence angle, but other considerations tend to limit what hood aperture size is practical for a given installation.

With respect to the comment by Rich Porter above: "Only 40% of the heat from a gas stove goes into the pan, 60% goes into the air. 90% goes into the pan with induction," this only applies while heating up the contents of the pan -- significant when the content is a lot of water. Once the cooking surface is heated to the desired cooking temperature, the induction power vaporizes the contents just as the gas power does. The induction-heated cooking effluent uprising and expanding plume will be the same as the gas-heated cooking effluent for the same pan temperature. The gas combustion effluent adds to this cooking with gas.

I can assure the reader that without adequate ventilation, induction cooking is perfectly capable of filling a house with moisture, grease, and odor.

kas

Rich Porter - an exhaust fan of 300 cfms at ceiling height is a lousy idea. As has been written above on this thread, it doesn't matter much that the cooking method is induction. I hate to think that people are clicking on that video and thinking that anyone should follow that model. Even setting aside the low cfms and at such a height above the cooktop to be useless, how is it cleaned? A typical exhaust fan has baffle filters, mesh filters, or a squirrel cage housing that collects the grease from cooking, and which is typically put in the dishwasher and/or wiped down to clean that grease. Does someone have to climb a ladder to clean those louvers? And when they don't, that pristine whiteness will become marred by grease stains, as will the light fixtures directly in line over the louvers.

What a terrible idea.

Fire hazard. And against code. All cooking vents are required to have filtration.

Excluding the better suited commercial hood options, what one would need in a flush ceiling setup is a large area covered by mesh filters (for the lower air velocity likely to be achieved relative to baffle filters). I don't have any data on plume velocity at significant heights, so I don't know what velocity to aim for, but if it is half normal for induction, say 0.3 m/s, or a foot per second, then I would guess that somewhere between that value and half that value would be required for mesh air velocity.

Depending on ceiling height, the area covered by a flush system may need to be 2 feet beyond the cooktop on each side to achieve capture and containment given plume divergence and cross currents, making the overall area roughly 7 ft by 5.5 ft (38.5 square feet of mesh) for a 36-inch induction cooktop. Several dishwasher loads would be required to clean the meshes. Mesh removal and replacement without risking harm to the island surface below would require some care.

The estimated required mesh air velocity would require a specific flow rate of 30 to 60 CFM per square foot, or 1200 to 2400 CFM total. (The blower zero static pressure rating would have to be higher, possibly 1800 to 3600 CFM.)

This alone is getting us into the realm of commercial products, both for exhaust ventilation and the requisite make-up air ventilation, which may need to be conditioned, and which will have to have the same flow rate.

What may not be immediately appreciated by many of us who are enticed by the look and function of pro-style appliances is that the pros have huge HVAC systems backing them up.

kas

That has to be the dumbest thing I've seen regarding ventilation. It's really a shame we don't have a filter to remove idiots from the internet.

Kas, there are some of those ceiling installations that are designed for ultra-high-end residential. I'm pretty sure they still don't do as well as a proper hood, but they exist. And, as you said, they're big.

pillog, I hoped to show that for equivalent performance to a nominally-sized, normally-mounted hood, the requirements for flush ceiling capture and containment make it rather uneconomic for residential consideration.

A commercial ceiling register scheme is shown in this web page:

http://www.kitchen-ventilation.co.uk/heydal

Apparently this approach does not require intense UV for grease removal.

This question isn't sitting in a vacuum. Competing interests include the social use of the space. A bit less efficiency could allow a clear view that may be very important to the day-to-day family use. That tradeoff is the same as a hundred others you make as you craft what works for you within the limitations you have. Easily removable mesh screens designed for a hood and a remote mount blower with properly sized ducting is a relatively simple project.

Kas, that is very cool!

I agree about flush ceiling mount being most financially inefficient for residential use. I was just mentioning that residential units are being made. Sometime in the future they might trickle down to the accessible if there's enough demand.

In case it isn't obvious, I have no objection to a flush configuration so long as is is based on the knowledge needed for it to be effective. For those happy with ineffective, then there are plenty of examples to follow in magazine photos.

kas

Not intending to high jack the conversation, but it seems very relevant to this discussion. I have not read all of the posts but I did skim and did not see this mentioned. I live in a condo and currently have no ventilation above my electric cooktop. The unit originally came with an over-the-range microwave but that was stolen (it was a foreclosure and we do not have a use for a microwave). I cook a lot and I regularly sear and pan fry. While the smell of cooked food does linger, it is not that bad and we prop up the doors and windows if it gets too smokey (very rare). If i cook dinner at 8, the smell is gone by the time we go to bed. I should also add that I live in a large open plan loft. The only rooms are the two bathrooms, everything else is in the same large two story space (living room, dining area, bedroom, office, kitchen). I keep my kitchen pretty clean and I am surprised at how not greasy things are, even above the cabs.

From the missing microwave, it is clear that the hood it provided did not actually vent out of the unit. There is no duct work for over the range ventilation. I suppose, even without proper venting, the microwave/hood combo will at least capture some of the grease and filter any smoke. I have also checked our contract documents and learned that it is not possible to add venting outside of the building. This is one of many oversights on the part of the builder with regards to future improvements owners may desire.

I plan to add a 36 inch induction cooktop and I do not plan to put in an over-the-range microwave as I do not like that look. I suppose I could add a hood, but it would really just be an air circulator with a filter. Seems an expensive addition for limited functionality. Full disclosure, I have not done enough research to even know if you can get stand alone hoods that are not hooked up to vent outside of the room.

What is the recommendation here?

I also have an open-loft (mostly) condo also without external venting. We put in an under-cabinet recirculating hood (Zephyr). It does a great job of sucking moisture and smoke up into the filter. It's not like the external-venting hood I had in my previous home, but it's far far more effective than the OTR microwave-hood I had a couple of years ago in a rented apartment. My cabinets are clean (not greasy or warped due to moisture). Smells do linger longer than they would if I had an external-venting hood. Yesterday, I was carmelizing onions, which took hours. On level 1, we could smell the onions cooking, and our eyes were still watering, but on level 2, neither of those things was true. The smell was there after the fact, but it wasn't strong.

This is quite an interesting thread! This isn't my usual "gw hangout" forum, but I'm getting an induction cooktop and googled the question. Interesting to note that an induction cooking info website was listed first and this thread was second.

While a couple of commenters mentioned they don't cook much, no one brought up how often people cook, what they cook, or for how many, in their arguments for having a vent. If I live alone, am a vegetarian, and use my cooktop to steam veggies, my ventilation needs are different than if I'm frying hamburger every night for six kids. Hoods are critical for gas stovetops, which is why they were invented in the first place--so people wouldn't get carbon monoxide poisoning. Now we've added the requirements that we don't want cooking odors to linger, nor do we want grease buildup in our kitchens. And nobody likes their smoke alarms going off, especially if they live in an apartment/condo. I'm fully on board with all of the above. But the reality is that a lot of people don't use their hoods because they're very loud, especially the cheapy ones in a lot of apartment buildings. For my needs, and I'm the aforementioned single vegetarian, I'm getting a GE OTR microwave/steam oven combo. It's got 400 CFM, more than adequate for my 900 sq ft home, and it recirculates the air through a charcoal filter; it does not vent to the outside. As has been pointed out, different people have different needs and priorities, so I say, as long as what you're doing meets code and is safe, then you have to weigh everything that's been said here and then make your own good decision as to what's best for your unique situation. I've done my homework and feel confident and comfortable with my decision. And yes, I'm one of those people who does indeed use my fan every time I cook. But I harbor no judginess towards those who don't.

Debbie B.: Please let us know how your plan works out. I think boiling veggies requires nothing more than moisture capture, and then only when humidity is high. Maybe some odor filtering is desirable boiling cabbage. The purpose of baffle filters, after all, is grease capture. In commercial settings where odor capture is needed, the hood filters may be different.

If the hood performance affects resale value, or you plan on entertaining carnivores, then better hood grease capture and containment performance would be desirable.

kas

So I'm in the planning stage for replacing a Jenn-Air 34" gas cooktop with their downdraft vent system. I'm planning on going induction, but don't know what to do for venting. The existing island is two levels with a 6" or 8" rise directly behind the cooktop for a elevated two seat bar setup. The counter is granite, but there is another catch. I think the original cooktop was electric in a 36" size. The Jenn-Air is only 34", so they made a picture frame arrangement that they cemented to the original opening, making a smaller size hole. Now I'm looking at attempting to remove this picture frame molding before I can see what I'm going to be dealing with.

Fast forward to the issue of changing the venting arrangement. The current vent dumps into the crawlspace below the kitchen. It isn't vented to outside - not a very good idea. I'm trying to decide what to do when I change to induction. I also have a obsolete concrete tile roof. So attempting to put a vent into the roof is risky. I'm also in a desert like location that requires AC for 6 to 8 months of the year. If I install a vent that exhausts the air, I'll be refilling my home with exterior temp air in its place.

So I was wondering how well the recirculation option would be for a overhead hood vent. Does anyone have much experience in how well the recirculation vents are? Do they do a decent job, or are they worthless? I'm a newbie, so please be gentle with your comments.

Thanks, Dennis

Dennis, you are in the right historical period for a solution. I don't think there were many (or any) effective recirculating vent systems decades ago, but on this forum over the past few years we have learned of several users' satisfaction with them. One report is earlier in this thread, although it is for a down-draft (maybe side-draft) and might not have full capture of hot cooking from all burners.

We have also heard of a Vent-a-Hood recirculating hood that its owner liked, and there may be suitable hood models from Broan/Best/NuTone, Modern Aire, ProLine, and Zephyr, to name a few. A search on this forum for "recirculating hood" may lead to relevant threads. I notice that the hood vendors are calling them "ductless" now, so that could be a useful search term for general information. Often these are kits added to otherwise standard hoods in place of a duct system.

Essentially, to be effective with full spectrum cooking, the hood will require baffles (or VaH's impeller blowers), and charcoal filtering at a minimum. Best would be baffles, mesh filters, and charcoal filters, with blower fans rated for high enough zero static pressure air flow rate to still be effective with all that restriction to push air through. You will want to ask the manufacturer what the flow rate is with the recirculating kit in place. It is desirable that it be at least 90 CFM per square foot of hood entrance aperture.

It is worth pointing out, perhaps, that for general commercial cooking, and residential pro-hood cooking with baffles, the intent is for the baffles to collect the larger part of the grease particle spectrum, with the rest swept out of the duct system to the outdoors. See plot below. With a recirculating hood, more types of filtering are needed if the smaller particles and odors are to be captured.

kas

Caveat: Before I take hood satisfaction seriously, I try to find out if the user smokes, has other smell/taste issues, has indoor pets, and especially cat boxes, etc. Good enough for a noisome environment and good enough for people who don't even like good cooking smells are two different beasts...

It really may come to the point where you aren't frying much. We make a large batch of vegetable/fruit slaw with only the peppers cooked. Everything else is raw. Tossed with wine vinegar it stays fresh in the frig until dressed with each persons preferred adds. 15+ different rices, grains and beans are boiled together, put in containers and frozen or kept in the frig. Some meats and fish are slow cooked in bags. Even hamburgers are slow broiled with a thermometer. Steaks only get 2 minutes on a side after baking in the oven to temp. There are many more cooking options used today. Frying and strong ventilation just isn't used enough to justify a major installation with makeup air.

Good point, pillog. "...good enough for people who don't even like good cooking smells..." is closer to my, er, taste, as you may have guessed by now. I would admit to a few exceptions, such as cilantro doing its thing and baking bread.

Some good points here!

We are debating gas (which we had) vs induction stove and I wondered if we would need venting. We used to have one of those microwave not venting to the outside but makes noise things which I would only turn on (and opened windows) if the smoke alarm went off.

Never noticed smells or grease. In fact, I did not know there were replaceable or washable parts in kitchen hoods although my husband says he has washed them! Who knew! I'm not very domestic.

So, I thought I will not need fan over an induction stove located in front of a tall window-like opening to my solarium. But, the house is going from leaky 1850s upstate NY fossil to 100% spray foam insulated, radiant floor heated, "can be heated with a candle" super tight house. And I am now thinking about a gas slide in with two induction burner cooktop next to it.

Bathroom we went with inline ventilation fans, though I did consider ERV/HRV.

This is still an unanswered question in my mind. I am leaning towards putting in the ducting for a real ventilation fan since everything is open now but maybe then just a bathroom type fan located much higher than real kitchen ventilation should be in a soffit. That gives a future option for a hood should someone decide they need all this aerosolized grease and odor capture stuff in the future.

I'm the kind of person who loved my kitchen in Hawaii because the dark granite counters with garnet showed no dirt even if there was a fine sprinkling of red dust everywhere.

These folks with the all white kitchens clearly aren't working the hours I am and don't have two dogs who outweigh me individually plus a husband who does construction and farm work. We don't have upholstery or curtains - just wood, glass, leather and tile. I guess I might not notice a stick of butter smeared all over the walls and furniture. Or maybe the dogs will lick it off!

island2island wrote, in part: " I guess I might not notice a stick of butter smeared all over the walls and furniture. Or maybe the dogs will lick it off!"

Truly a green recycling approach to kitchen ventilation (as long as the dogs go outside). And no make-up air needed, except for breathing.

A gas cooktop may require a hood venting to the outside for safety reasons; check with your code enforcement officer.

With a gas cooktop and auxiliary induction, you would need a wider than normal hood to capture most of the cooking plumes' effluent. In the image below, the hood is used for capture and containment from a 36-inch induction cooktop and a separate induction wok cooktop.

(Apologies for not rotating the image before submission.)

A modest ceiling vent will only help remove odor over a long period. It will not starve your dogs of essential grease deposited on walls.

kas

That is a great layout, kas! I feel an urge to teppanyaki for an audience!

It's difficult explaining how our range will be set up (I say it's in front of a window that's not an actual window) but it is just like this except the seating/passthru counter is another opening to the right and the stove will just be in front of a plain opening. Is this your kitchen?

I'm having the hubby put in a duct. Might as well take advantage of no charge change orders. Mennonites are already working on cabinets so can't make changes there, but I think we will mount an under cabinet ventilation thing in a soffit over the opening. Hubs used to run a drywall crew so a soffit is "easy". I irritate him a lot when I say, progress is slow but at least the labor is priced right! It will be a hand made house ;)

I cook a lot like bacon, scallops, stir fries, etc. I am planning to have my cook top on my island as well. I am thinking of putting a overhead vent and a popup to prevent the grease going on the otherside of the stove to where people are sitting and to keep the smell from going across the whole house. Has anyone tried this before? Seems like it would be pretty effective.

ConSys, back in 2003 I got a JennAir radiant cooktop with a strong central downdraft. My kitchen designer suggested getting an additional overhead vent since she'd heard that downdrafts weren't very effective. I liked that set up. It didn't catch every splatter of grease (nothing does), but using one or the other or both did a good job of catching steam, or eliminating smoke & smells, & kept grease splatter down. I liked too that the downdraft could be used to draw cool air over hot pies or cakes from the oven (user manual suggestion). Admittedly, cleaning the downdraft was a dreaded chore; I did it about 3 times a year as the JennAir downdraft wasn't an easy thing to clean.

I love my new Wolf induction cooktop, but miss that central downdraft sometimes. The overhead is just ok for my cooking. But my husband cooks things almost daily that send grease splatter everywhere & the overhead is inadequate for that. Grease splatter screens don't help that much. I go through a LOT of paper towels cleaning the cooktop area.

So, yeah, I think it would be fine. It's an unusual set up, & most posters here are reluctant to veer from the conventional, so expect countering opinions. But in my experience, it worked pretty well.

Thanks for the input. Good to know that these pop up vents are tough to clean. Hopefully a vendor has taken note of that and engineers a more practical solution. I will look around. If anyone has input on pop up vents please let me know! It would be a pain cooking for the kids and the grease splattering all over their homework or laptops or whatever. That’s exactly what I’m trying to avoid.

2 fans blowing in different directions will be far worse than a great single fan, with a great capture area, doing what it's good at doing. It will create huge turbulence and air swirls that just let go of the grease everywhere.

One fan is pulling from the top while the other is pulling from the back. They are pulling air not blowing air. Engineer here trying to understand how your physics are being compiled.

Plus, at least in my situation, the power of the fans wasn't equal. The downdraft was stronger & grabbed outflow from the source (pan). Seemed like whatever wasn't grabbed by the downdraft wafted upwards & was grabbed by the overhead. The idea of creating turbulence sounds right, but maybe it was turbulence in the right directions? Anyway, it sure was useful for clearing the air if I burned something in the wall oven.

OK, youall have succeeded in drawing me into another argument. Let's start with the purpose of the overhead vent. The vent is intended to capture and contain effluent contained in the rising and expanding cooking plumes. It has an overlap capture requirement that depends on height, and a flow rate containment requirement that derives from plume velocities and secondary factors. It is not for capture or blockage of grease splatter, as that could require enormous air velocities to achieve.

Down-draft "venting" and pop-up side-draft "venting" cannot achieve the needed capture and containment provided by an overhead hood of proper specification for these reasons: Air flow velocity drops rapidly as a function of the smallest dimension of a slot air intake (see the 2003 ASHRAE HANDBOOK, HVAC Applications, Fig. 6). The air velocity in all cases is too low to significantly change hot cooking plume momenta except those plume portions close to the pop-up, so the overhead hood depends on the natural rise of the plumes. Deviation of the upward momentum to the side, or by 180 degrees to head downward, can only work if the plume has low momentum, as in steam from boiling water. Hot oil/grease/moisture plumes from wok cooking and searing will be poorly deviated sideways or in reverse.

Fume hoods can have horizontal hood configurations, but the top and sides are blocked from allowing fumes to leak out.

The turbulence issue is complicated. Up-rising plumes can be disturbed by side drafts, poor insertion of make-up air into the kitchen, and cook motion. Side-drafts will be pulling air across pan and pot clutter, so some added turbulence is possible, but I don't think it will be a significant addition except close to the pop-up due to the velocity fall-off introduced above.

On the other hand, a pop-up can block splatter trajectories from the burner up the the angle between pan and the top of the pop-up and as far as the pop-up sides shadow the area beyond. For this function, no air flow is needed and much of the pop-up system hardware can be dispensed with. If a blank face is used (no vent holes/slots), cleaning may be greatly simplified. Underfloor ducting, blower, external cap can all be deleted. Some cabinet space for the elevation mechanism has to be sacrificed.

While a pop-up splatter blocker is a good idea if the degree of blockage is deemed sufficient for the expense, the subject raises the question of why children are sitting in range of hot grease splatter. At a minimum they would need eye protection. There are requirements (that I don't have at hand) for desirable rises and/or runs of seating countertops connected to cooking surfaces.

I recommend proper desks in quiet areas for studying. The student should be fully absorbed into the material to be studied without distraction (or at least as little distraction as a post pubertal youth can manage).

Well, my dear kaseki, I bow to your technical expertise (of which I admit to having none). But all I know is I had one of these for 17 years & didn't find it awful:

I'd turn the vent on high & could feel air drawing across my face. My cooktop is on an outside wall. You could feel, hear, & smell the vent exhaust if you were near it outside. We don't use a wok, don't sear steaks, but we did use the grill for hamburgers a lot. The vent evidently captured something, because it would need a thorough degreasing periodically (Yuck!) Overhead was (still is) a low level Broan, which I think is only 300 cfm. It's ok for steam rising from big canning pots & clearing the air of cooking smells. Maybe I just don't know what I'm missing because I've never had a powerful overhead vent that could suck up a nearby hippo. But this old set up worked fine, I thought, for cooking family chow. I never felt a need for anything better.

p. s. Not an argument, just a spirited discussion :)

Hippo class ventilation fan; high initial and operational cost, but you get what you pay for.

kaseki, think of the make up air required! Kitchen as wind tunnel :)

Thanks for the humor.