I badly wanted to go with induction, but our island doesn't have sufficient wiring...only 20 amps. To get the required 30 to 50 (depending on number of 'burners') would have cost at least $2000, if it could be done at all. The wiring doesn't always run through conduits, or at least that can't be determined so far, so new external conduits are required for the length of the house, then sheetrock removal once the wiring re-enters the house. Still investigating though. Where is the electrical panel located on, or within your residence? Have you had an electrician examine your situation with your telling the electrician what you have in mind? Since you have a poured slab some of better layouts do accommodate with extra stub-outs for electrical runs; you make have an extra run hidden underneath the floor of the cabinet base. An electrician has the tools to locate your electrical run throughout the slab, and walls, without demolition. If you had your heart set on something, you should try to achieve it versus having to live with second best as you will be living it for several years after the decision has been made. Regarding your downdraft fan, and from personal experience, here is what I look for: 1) Ventilator height; the taller, the better. 2) Variable CFM capability; there is nothing like evacuating smoke as high-speed when you accidentally burn food, and smoke alarms are wailing. 2) An external fan as pulling air out is better than pushing it, plus the noise reduction is well worth it.

Hi FoodJaunts, No, my cooktop is not the matching GE, it is a KitchenAid that I got from a scratch and dent dealer new, in a badly beat up box, but the cooktop did not have a scratch on it. It's MSRP was $2800 and we got it for $1200. Like you were planning, our blower motor is in the basement, so there is no need for a bigger base cabinet. So you are not flipping this house, you are buying it to live in, from a flipper, and because he has not yet done the work, he is willing to install the appliances of your choice if you pay the difference, right? If flickering gas was the only problem with downdrafts, I would say that getting an induction cooktop with a wok burner would be a good idea (they do make burners shaped like a bowl to accommodate a real round-bottomed wok). HOWEVER, my set-up does not pull grease and steam from the front burners. It gets most of the steam from something cooking on the back burner, however. I would not expect my set-up to work for stir frying. DH agrees, saying, "not unless it was a really short wok and really close to the downdraft!" Anyway, here is an inexpensive portable countertop induction wok burner: http://www.amazon.com/dp/B004UI882A/ref=asc_df_B004UI882A2252470?smid=A294BYNQDK07T&tag=nextagusmp0355811-20&linkCode=asn&creative=395105&creativeASIN=B004UI882A and a discussion about that burner and about cooking with woks using gas, electric, and induction that I found very interesting. http://www.cheftalk.com/t/68139/adcraft-wok-induction-burner I also found this expensive built-in separate wok burner: http://www.katom.com/084-MWDG1800.html?CID=Nextag&utm_source=Nextag&utm_medium=CSE&utm_campaign=CSE&zmam=29342707&zmas=1&zmac=3&zmap=084-MWDG1800 But look what Dacor is now making - a 15" high downdraft pop-up with up to 1000 CFM external remote blower. They show it on a serious gas range and talk about "capturing smoke and steam from all of the burners:" http://www.us-appliance.com/erv3615.html And Miele has one that rises 14": http://www.us-appliance.com/da64901000.html You can always look into getting the 48" downdraft with your gas cooktop, then put the induction wok burner beside the cooktop, right under the downdraft. The chef in the discussion likes the induction with the round wok bottom better than residential gas burners and a wok. So things are looking better in the downdraft department. I wish you the best of luck in your endeavor to find the right system to work for your family. Here is a link that might be useful: Built-in induction wok cooker

@bcarlson78248 - can spray foam cover the entire 6" duct (i.e. without anything else to fill the gap) @energy_rater_la - the exterior is fiber cement siding. I have posted some pics of the duct/wall cap. I have removed the the old cooktop and some of the metal vents. The one attached to the vent cap is remaining (I think foil tape was used to attach this to the wall cap). I don't see a way to remove this last metal duct without removing the vent cap from outside. I was thinking I will leave it as is (and cover inside with fiberglass/foam) - or see if I can cut using some tin snips to shorten the length. How about using a duct cap on the inside to close it off (like the one in http://www.homedepot.com/p/Master-Flow-6-in-Round-Duct-Cap-DC6/100396933). Outside wall cap: Metal duct left on the inside:

Can I just say that whenever I try to discourage people on this forum about a downdraft (when they have other options like in new construction or a complete reno), I mention downdrafts are hard to clean, and that the grease exits under the floor, but then where does it go. I get back...nothing. Generally I am ignored when a poster is determined that downdraft is what they want--because a ducted hood is just such awful choice by comparison (sarcasm there).