I'm also researching range hoods and have noted that your selection from Home Depot is a wall mount, not usable for an Island (since you have no wall to put it on.) You need to look for one that specifies Ceiling Mount or Island Mount.

Vocabulary can be a slippery thing. From your photo and your budget, I'm guessing that you aren't actually thinking about a "stove" or "range" -- at least, not as those terms are usually understood around here. Am I correct that what you want to do is yank out that radiant electric downdraft cooktop (Jenn Aire?) and drop in a 36" wide induction cooktop while adding an overhead vent?

Also, am I correct that budget of $3k has to cover both the cooktop and vent hood?

If so, I have some suggestions for things to consider.

First, cooktop cutouts sizes vary between model years and brands. You might be able to open up the cabinets and drawers in the island and find a way to measure the dimensions of the existing cut-out from below. Or, take your cooktop's model number and do an online search for a pdf of the install instructions which will have the dimensions of the cut-out. Then, check those specs against the specs for the induction cooktops you might be considering.

Depending on the particular induction cooktop you are considering, it might: (a) fit in the existing cut-out; (b) you might have to trim one or more sides to enlarge the cut-out (which means budgeting for the work unless your countertop is something other than the stone it looks like in your photo and you have the diy skills and tools to make the necessary cuts); or (c) the existing cut-out may be too big for some induction cooktops, in which case you have to figure out how to (and budget for) build up the rim support under the cooktop.

Second, I'm recalling that some of the older Jenn Aire radiant electric downdraft cooktops were actually 42" wide. Is yours one one of those? If so, it rather narrows your choices of induction cooktops. All of the 42" induction cooktops --- at least all of the ones that I can think of off the top of my head --- are from expensive brands like Miele which will eat up most of your $3k budget. If your present cooktop is a 42" model, you might consider going with a 36" model and have some sort of cosmetic and structural cover fabricated (maybe in stainless steel) to cover the gaps and provide support. I'm guessing a new countertop for the island is not in the budget.

Third, Green Designs mentioned a possible need for an electrical upgrade. Here's what that means if you did not understand the comment. Some 36" induction cooktops can run on a 40 amp circuit but many require a 50 amp circuit. Not so many years ago, 36" radiant electric cooktops might only have been wired to a 40 amp circuit. Seeing the existing downdraft radiant cooktop makes me suspect that the existing electrical circuit probably is a 50 amp circuit. Only you or an electrician on site can determine whether that is the case. You need to verify that you already you have 50 amp service (checking the circuit breaker may be the fastest way to do that). Otherwise, there are not many 36" induction cooktops that now are rated to run on a 40 amp circuit. Frigidaire comes to mind as one, and worth considering in light of your target budget.

Fourth, the vent hood is going to be more expensive. As Jaykaym says, the Home Depot unit is out of consideration because it is a wall hung model. The linked Cavaliere is an island hood but it is only 30" wide, which is too narrow for your cooktop. At least, look at the 36" wide model.

The basic problem you have to solve with any hood is that steam and etc. spread out as they rise. Think of the plume of cooking effluent as an upside down cone that gets wider as it rises. You want the hood wide enough to capture as much of the plume as possible. so that the fan grabs as much of the plume as it can. Too small a hood and, no matter how powerful the fan, you will be raising the plume up higher and spreading some of it further around the kitchen. Lots of very detailed advice here on fan and hood sizing over the years (particularly from Kaseki, our resident vent guru) if you care to search for details. The rule of thumb around here for decades has been that you want the hood to be at least three inches wider in each dimension than the cooktop it hangs above. With a 36" wide cooktop, the standard advice is to look for a 42" wide hood. You can go narrower with a wall mounted hood because the backwalls and cabinets to help confine the rising plume. No such aids for an over-island hood.

That said, budget constrains your choices, which likely means looking at something for $100 more, such as the 36" version of the hood in your link. It will be better than nothing and, indeed, will be noticeably more effective than the existing downdraft unit. Be aware that running a 900 CFM fan into a 6" duct will be considerably noisier than better (but maybe less affordable) choices.

Fifth, speaking of that 900 CFM fan, have you looked into make-up air (MUA)? Do you have any gas appliances (say, furnaces or water heaters) or fireplaces? Unless you have an adequate source of MUA for what your hood is sucking out of the house, running a strong vent fan can backdraft copious amounts of carbon monoxide into the living spaces. Also, more and more localities are adopting code provisions that require MUA for range hoods with fans rated to draw 400 cfm or above. Best check your local codes before anbody starts cutting holes in the ceiling and roof.

The installed cooktop appears to be this downdraft Jenn-Air JED3430GS 30 Inch Electric Smoothtop Cooktop.

How about replacing it with either a 30" or 36" induction cooktop and downdraft vent:

• GE PHP9030SJSS Profile 30 in. Electric Induction Cooktop ($1529)
• GE UVB30DKBB 370 CFM 30 Inch Wide Downdraft Hood ($872)

-OR-

• GE PHP9036SJSS Profile 36 in. Electric Induction Cooktop ($1800)
• GE UVB36DKBB 370 CFM 36 Inch Wide Telescopic Downdraft System ($872)

...which would be underbudget and eliminate the need to tear up the ceiling and roof?

What jwvideo said. But there is also more to describe.

Is this hood going to interfere with sight-lines? Raising it above 36 inches will require it be larger in breadth and depth than at lower heights above the counter.. At 36 inches, it should be at least 6 inches beyond the widest pan that would be used on any burner (hob). This overlap should grow at 1.5 inches per 10 inches if you start raising the hood to clear a sight-line. Do not go higher than 4 ft above the cooktop. If the area is subject to cross drafts, even from moving people, the hood entry aperture will need to grow further. Do not assume that just going wider will be sufficient; for island hoods the front-to-back depth has to overlap the pans just as the side-to-side overlap does.

The hood needs some volume below the baffles to retain transient plumes that may exceed the capability of the steady-state hood flow rate.

Do not expect a specific flow rate of less than 60 CFM/sq. ft. of hood entry aperture to effectively capture and contain typical induction cooking plumes, and 90 CFM/sq. ft. will be needed if any searing or wok cooking is envisioned. After multiplying one of these values by the entry area of your hood (as determined by overlap rules above), multiply by a further 1.5X to find the approximate blower rating needed to cause that flow rate past the entry aperture. The MUA blower will need to be of similar size or else a very low restriction (large) passive duct will be required.

Size the exhaust duct to achieve 1000 to 2000 ft/min flow velocity with the actual estimated total hood CFM. A duct meeting this flow rate will have lower pressure loss than the baffles, for reasonable duct lengths. This means, for example, that a 900 CFM rated blower used with an 8-inch duct and nominal baffles (and compliant MUA) will probably flow 600 CFM; a 6-inch duct would restrict the air flow significantly more, as well as adding noise.

For lowest noise, use an in-line or external blower with an intermediate silencer.

With respect to your option 2 hood, this design is unsuitable for its purpose because it does not correctly capture rising effluent without spillage.

With respect to your option 1 hood, this is a more conventional design, albeit too small for real use on an island unless only modest cooking is performed using only the middle hob. If it could actually achieve 600 CFM with a 6-inch diameter duct, which I doubt it could with a 10-ft long duct, the flow rate in the duct would be 3000 ft/min.

Note that the choice of separate cooktop and pop up downdraft isn’t easily retrofitted. It requires more room, and existing islands may need to be completely rebuilt to accommodate that. If that is to happen, the overhead option will always be the better ventilation option, and for about the same money.

Is the space above your kitchen unfinished attic space, or finished living space?

Long time! Thanks to all your ideas , had installed the Cattura Best Range Hood and it was a great choice! Working perfectly after all these years, and they have great customer support and technical support! No need to spend on expensive ceiling range hoods, if you do not want to wreck your ceiling.