We have the cattura in our new kitchen. It does a pretty good job on the two highest settings and works and looks much better than the kitchenaid downdraft. Provided much better options for venting configurations than any of the other downdrafts we looked at, so that is a definite plus. It is still a downdraft though and not as effective as an over range hood, but I was willing to sacrifice a little effectiveness in order to be able to not stare at a wall while I cook/prep.

I used a downdraft with a gas range in a rental. I hated it. It was noisy, ineffective, and disrupted the flame. It was completely useless when I was using a pot taller than the downdraft (e.g., when making pasta) or when the pot/pan I was using wasn't directly up against the fan.

It was a rear telescoping downdraft.

In my view, it is a valid financial position to decide that proper ventilation is unaffordable, leading to choosing to have no ventilation, or minimal ventilation that can only slowly clear the air; in either case accepting that grease and odor will drift into the house and coat its walls, ceilings, and fabrics.

It is a valid aesthetics position [albeit one I don't embrace] to argue against a hood blocking a sight line, but then the consequences have to be accepted: Either there will be grease distributed throughout open parts of the house, or cooking has to be restrained to only the most modest temperatures.

It is not a valid technical position to ignore the well reported facts related to cooking plume capture and containment that require an over-cooktop hood with sufficient size and air flow rate to be effective. Given the cost of side-draft systems, and the limited* hot-cooking side-draft effectiveness at practical (for non-industrial use) air flow rates and attendant sound pressure levels, one might as well apply those costs to an overhead hood.

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*If requested, I will provide both a plume velocity reference and a hood flow rate contour reference along with a gedanken experiment that should justify this assertion.

Most people moving cooktops from one spot to another are doing the opposite of what your OP said. People want to move the cooktop from the island to the perimeter, so that they can exhaust it properly. Also, with a downdraft, the smoke and grease have to go somewhere - are they just going to sit under your kitchen island and there will be a duct or capture of some kind there? We have seen posts talking about how disgusting that is to clean, since there is no place for the smoke and grease to go with the downdraft. Or, it can be exhausted out of the house, but because it's a downdraft, the smoke and grease are having to travel down and out, rather than up and out, which as mentioned above, goes against the laws of physics, which is why a downdraft is never as effective as an overhead exhaust.

Horizontal exhaust ducts need some slope to assure that grease doesn't pool in the duct. A one-quarter inch per foot slope is recommended based on commercial requirements unless the manufacturer's design is rated for a lower slope angle. I further suggest that any such ducting installed in a crawl space have an easy means of inspection and cleaning. NFPA 96 may be a useful guide to avoiding fire hazards. The flow velocity range of 1000 to 2000 ft/min intended to minimize both condensation (low velocity) and impingement (high velocity) grease accumulation should be a goal. Cold is an enemy for grease accumulation, and heating the duct by running the ventilation a bit before generating greasy effluent plumes may help, depending on duct exposure to environmental temperatures.

IMO you are spending too much money for too poor ventilation the best place for a cook top is an outside wall or at least a wall where the venting can go straight up and out

Besides the points outlined above, you are installing a gas cooktop you said. The gas flame will be pulled sideways and/or down by the downdraft.

Me, I like an island to be an uninterrupted expanse of counter so that I can prep on it, and sit with my family at it.

Post a to-scale overhead view of your current kitchen and surrounding rooms with all dimensions shown, along with your goals for the remodel. There are some folks here who will help you get the most functional layout so you can get the best bang for your buck in your beautiful new kitchen!

Back to the original question about fitting a downdraft. I have a regular tele downdraft in an island. Of course it is behind the cooktop. That gives room for 16" drawers below the cooktop which is plenty of room for all pots and pans. You do have to leave a little room at the back but its an island; what's the problem? Yes, a downdraft pulls the flame. Induction would be much better. Of course its not a real hood but it will catch smoke if you burn something (on the back burners anyway). I used to fry lots of chicken (long before I had this configuration) but fortunately don't anymore. I'm not sure a regular hood would catch all that stuff anyway; a splatter screen would probably be better!

But regarding general gunk and cleaning, I have had this configuration for ~12 years and see NO crud on the ceiling. If you don't have a blast furnace below your pots/pans it may not matter.

"You do have to leave a little room at the back but its an island; what's the problem?"

@chas045 - well, that all depends on the size of the island, and on the size of the kitchen that the island is placed within. We don't know either of those things. So your "leave a little room at the back" could indeed be what is the problem.

Has anyone used one of these inceiling exhausts? Seems like they are popular in the UK but maybe aren’t common here? Just thought it might be a better option then an obstructive dropdown hood?
Or a downdraft

@K H - those ceiling fans allow too much space between the cooktop and the exhaust so that there is lots of opportunity for the smoke and grease to spread out and not get exhausted. But also, all kitchen exhausts need to be cleaned. Who wants to get a ladder out to climb up there to pull out the filter from the ceiling, and then climb back up to put it back. There were a couple of reports that people reluctant to do that and procrastinating it, ended up with drips of grease plopping down from the ceiling exhaust as the filter gets clogged from not being cleaned. Ew.

@Shannon_WI gross what the heck are they cooking lol! Even the regular wall range hoods look like a pain to clean. So why so much hate on the island cooktop?

For the same degree of performance (capture and containment), a wall hood configuration will require a smaller hood than an island hood, with commensurately lower volumetric flow rate for both the hood blower and the make-up air blower. If visual blockage or appearance drive an island hood higher, then the capture area has to grow as the square of the height increase, as do the two flow rates. Everything gets larger and larger as one goes up. The ceiling systems sold for residential purposes are generally too small for full capture, and likely will not have the flow rate needed. Cross drafts become an ever greater problem with large gaps between the cooking surface and the capture aperture.

Tour this site for a real ceiling system: http://www.kitchen-ventilation.co.uk/heydal

"You do have to leave a little room at the back but its an island; what's the problem?"

@chas045 - well, that all depends on the size of the island, and on
the size of the kitchen that the island is placed within. We don't know
either of those things. So your "leave a little room at the back"
could indeed be what is the problem.

Well actually I was in error. My telescoping downdraft is a basic standard model and all of the mechanics extend to the front so no additional depth is required in the back. By stating that it is a standard model is to point out that one certainly doesn't need some special expensive unit.

The OP (who BTW hasn't returned), also asked: 'We are on a crawl space -about 4 feet high. Does anyone have any experience with downdrafts and.......'

Mine is in a similar situation. My original installers didn't have any problem installing the unit and running vent between two floor joists to the outside wall. Obviously you need access all the way. I had to remove the downdraft to extend the counter depth opening an 8th of in inch for a slightly larger replacement cooktop. I needed my wife's help from the kitchen to reattach the vent while lying in the crawl space but it wasn't a real problem.

To address the issue of a cooktop in an island...

An island is generally the preferred location for working in the Kitchen. So, let's look at what work is being done and how much time is spent doing it:

• 70% of the time spent and work done in the Kitchen is prepping -- preparing a meal. E.g., cleaning/rinsing food, cutting up food, mixing food, other prep tasks

• 20% is spent cleaning up -- all cleaning tasks. E.g., clearing & wiping down the counters, clearing & wiping down the table, scraping dishes. loading DW, sweeping, unloading the DW, other cleaning tasks

• 10% is spent cooking. This means actually watching food cook, stirring, adding ingredients. The vast majority of food does not have to be "watched" all the time, just the occasional check/stir. Yes, there are some exceptions (e.g., egg nog that needs constant stirring), but those things are few and far between.

What task, then, does it make the most sense to put in the island? Look at the task with the longest time spent/work done -- prepping. This means the Prep Zone. Not the Cooking Zone, which is the least time spent.

Now, if putting a cooktop in an island is your "dream" (like in cooking shows where they are demonstrating for the camera what they're doing), then size the island so it can accommodate both the Prep Zone and the Cooking Zone (with appropriate clearances for safety of traffic and visitors, of course!) while while maintaining adequate aisles all around the island.

Example:

1.5" counter overhang

+ 24" cabinet (for emergency landing space & safety margin for traffic)

+ 30" cooktop

+ 36" workspace (bare minimum recommended for prep workspace)

+ 18" prep sink base (minimum recommended size)

+ 12" cabinet (for landing space & minimize splashing)

+ 1.5" counter overhang

======================

123" (10'3")

In addition, there should be at least 24" b/w the back of the cooktop and the seating overhang behind it to minimize splattering your visitors with grease or inundating them with steam from boiling water. If you have a downdraft, then I'd put even more b/c that downdraft will be very unpleasant to sit behind!

So, the minimum size of your island should be:

• Width/Length: 123" (10'3")
• Depth: 49.5" (1.5" overhang + 24"D cabs/cooktop + 24" behind cooktop)
• Note: If your Cleanup Zone is also in the island, then I recommend adding another 24" to 36" to the width.

Buehl:

Utilization: I agree with your points, but when using statistics as arguments one needs to be careful that the statistics represent all the applicable factors. For example, if the goal is to talk with guests across a kitchen work counter before a meal, it is necessary to rescale the percentages by the probabilities that the guests are present when cooking, prepping, etc. In the extreme case where one's guests are only there to "eat and run," then the prepping and clean-up fractions don't count. If one never starts clean-up until after guests leave, then that percentage doesn't apply. I think that there are other factors that can be at play in individual circumstances.

Facilitation: Nonetheless, cooking on an island with proper ventilation is more difficult to architect unless the ceiling - attic - roof path is as convenient to facilitate over the island as over a wall area. It is possible that incorporation of a silencer in an attic would be more difficult if the attic penetration from the kitchen is near the edge of a roof. But as noted earlier, the ventilation components will usually be more expensive over an island than at a wall for equal capture and containment performance.

Space: The need to count prep and clean-up space into an island greatly depends on the configuration of the rest of the kitchen counter space. If the prep and/or cleanup is done on other counter spaces, space for it need not be included in the island surface space.

Except...my point is that if you're going to put a work zone in the island, it should be the most used. If you also want the Cooking Zone, then both the most used + Cooking Zone should be planned. Most people want to work (prep 'cause that's the most work) on the island -- regardless of whether there are guests.

Obviously the OP's goal is not to have a clear workspace or even an "empty" island, so s/he must want a working island...so make it the most useful working island you can, which means include the Prep Zone.

Even if s/he doesn't realize how much work is prepping and just wants an island with a cooktop (i.e., planning to prep facing a wall or window along the perimeter instead of on the island), the island still should be at least 48" + the width of the cooktop wide and, assuming seating, 49.5" deep. (If no seating, then it can be 6" shallower since you really don't need any more than 18" behind the cooktop if there are no seats.)

Thank you for the advice. No, I’m not planning on being on the Food Network, but I guess I should’ve mentioned that I have an open concept home on the water in Eastern NC where hurricanes tend to knock out our power so a gas cooktop is a must for me. My current configuration has a two level island that seats 6 and is shaped like a half a hexagon. I love the shape but from my prep area on my current island to my cooktop is 10 feet. That’s too far and I don’t like facing a wall instead of my family /guests and the view of the water. I rarely fry anything but I do cook daily. I notice that many homes have the typical microwave above the stove configuration and wonder since those can only be recirculating fans -then maybe another option would be a nice hood that comes down from the ceiling but is a recirculating fan instead of exhaust fan? I have a bedroom above my kitchen so I can’t go up. I do have 10’ ceilings in the kitchen which open to a cathedral ceiling in the living room. I currently do all my prepping at the island and have a 13” wide vegetable sink. I’d like to stay with that size sink, and a 36” cooktop. The new island would be 90”x60 (includes overhang for counter height stools). I rarely use my current exhaust fan.

The typical microwave oven above a cooktop does very little in removing and/or filtering cooking effluent.

There is a VaH system (ARS) which reportedly is successful at capture, containment, filtering, and recirculation. One advantage is that no MUA is needed, which mitigates part of its cost.