Even in a alcove a downdraft vent system should be expected to miss a lot of effluent, but it is better than nothing.

Why is there a cold draft? There should be a damper between the outside and the vent system, or between the vent system fan and the vent aperture.

To get to the point: I deliberately bumped out the cabinet and soapstone counter where my induction cooktop is by three inches. Your reason is one of mine. I haven't noticed any snickering from guests, but don't have a statistically significant data base from which to draw a conclusion.

kas

Kaseki, thanks for the response. It's reassuring to hear someone else had the same issue. In all my searches either the cooktop being replaced was in an island w enough space or had overhead venting. As far as the cold air is concerned, I'm sure at some point there was a damper of some sort but it has long since broken. I'm sure if I took the time it could easily be fixed but I'm too lazy and just use the towel :)

In my case the cook-top is on a peninsula, part of which is a bar configuration, and I wanted to move the cooking away from the bar as well as shifting the island hood away from the bar.

However, I use a large island hood (also covers an induction wok hob) and it is about 34 inches above the cooktop surface. So with a high flow rate blower I can pretty much keep all cooktop effluent out of the house.

The difficult to solve problem is capturing oven effluent when an oven door is opened. I have registers above the wall ovens connected to a separate ventilation system that try to capture, but there is just too much spillage into the room upon door opening to be immediately successful.

The "eyebrow" scheme used in commercial cooking would be expected to be more effective, but far from fully effective. Any scheme built in by the manufacturer might dry out moisture in the oven unless a means of replacement were included.

You might consider ways in which your alcove could be enhanced to curl the effluent that passes the downdraft around where it might have a second chance for capture. Sheet metal formed to resemble a closed off recirculating hood might help.

Anyway, good luck.

kas

Don't assume that venting upwards would be cost prohibitive. If the alcove is within 30 feet of an exterior wall, it could be possible for a professional to route ductwork to the exterior. It's worth exploring before settling on a downdraft.

Thanks for the responses. I will look into those options.

I had a downdraft and just got rid of it. It was so ineffective and really effected the cooking temps of my gas range. I highly recommend not having a downdraft. It sounds like you could have a vented hood.
Good luck