I think you have not received responses to your post because on this Forum, downdrafts are very much disliked. Especially if you have the luxury of building new and therefore can install the ductwork for a proper hood. Typically, the only people who have downdrafts are those who are forced into it due to existing construction constraints. I am assuming your rangetop will be gas. A downdraft will pull on those gas flames. And, the laws of physics say that smoke and steam float up, so the downdraft is working against the laws of physics. I suggest you reconsider the downdraft for your rangetop, and get a proper hood instead. Many of the island hoods are gorgeous and will add "wow" factor to your kitchen. If you are worried about obstruction of a view or something like that, then get one of the glass hoods. Do a search on this forum for "island hood" and you will get a lot of threads to read.

I had a Thermador retractable that worked pretty well. It worked perfect on the back burners for anything I ever did. On the front burners if I wanted maximum venting I would tilt a lid on pan to direct steam & odors so I had good ventilation.

Only about 10-15% of your time in a kitchen is spent actually applying heat to the food. About 75% of the time, you're engaged in prep work, and the rest is cleanup. That's why it makes more functional sense to have the island be a prep space rather than a cooking space. It also saves THOUSANDS of dollars vs. going with an island ventilation system. Venting straight through the roof or straight out a wall is much more effective and costs much much less.

If your kitchen is a large enough one that you want your prep space to be beside your cooking space (you'll also need a prep sink for maximum efficiency on the island or else you'll be doing a lot of back and forth turning around) then an overhead ventilation system will be more functional and can be a great focal point to a kitchen. It really does not "close in" a kitchen, as it's above your line of sight.

We have a dacor downdraft mated with a Miele induction. The false hood above is lined with stainless steel. The cooktop is against a wall and it is 8 ft long. The first island behind the cooktop (42" space) holds ths double farm sink and is also 8 ft by 40". A prep area to the left of the sink DW to the right. With large double sinks any additional washings go into the left sink and any prep washing are in the right sink which is behind the cooktop. The second island is more of an entertaining area with wine fridge. The whole area is open to a great room concept. So bottom line we tried to setup a vent space in a number of other spots but this had the most function and form.

Thanks for all the advice,especially Mcmann who really summed it up well "think about how you cook". Actually we never even use our vent now unless we are burning or searing or deep frying which isnt that often. I dont think even if I lost some flame it would effect me too much

The kitchen we are building is huge at about 30 x 25 and has a 14 foot 2 tiered bar and lots of counter top and cabinets. We do have the prep sink too.

I know I can use this setup with a cooktop, but has anyone used with a rangetop that requires more height/depth ?

Thanks again

We have had the Dacor Epicure Cooktop (ESG 366 sch) for three years. It is one of the larger ones - check the Dacor website for photos - they still make the same model rangetop. Dacor offers 2 different remote blowers for the raised vent system- we went with the smaller one which I think is rated at 1000 CFM's, I'm not sure about the larger one, it might be 1600 CFM's- but it is huge and we didn't have the space on the outside wall where we wanted to install it. As it turns out, the 1000 one is fine.

There have been several posters here who have married the Dacor downdraft with a different brand cooktop - just like canuck did with the Miele induction.

Godd luck.