Evolution.
If you don't learn from your mistakes, you are bond to repeat them.

The ventilation is to cool the electronic controls. When I make a dozen or more quarts of spaghetti sauce at a time, on my 24" induction (same power as 2/3 of the same model at 36"), and it's simmering along for hours, all the ventilation air in the channel behind the drawers gets hot and the fans can't keep up. The cooktop will shut itself off to prevent heat damage. Opening a drawer before that happens is always a good idea.

My 1980s GE radiant had guidelines for space required underneath it to help with dissipating the heat it produced. Perhaps the fans are in conjunction with the lower profile so we have flexibility if we want working drawers underneath as well as insuring cooler electronics.
Electric cooktops DO need some way to move the heat away and manufacturers are addressing it.

Love my induction.

Simple answer: most cooking appliances installed in wooden boxes require cool air intake to offset the heat they create.

I just installed a new induction cooktop, replacing an old hallogen. The induction seems to produce a lot more heat underneath than the old radiant cooktop. Must be all those magnets. Some induction cooktops -- like ge -- require 12 inches of open space. It is good though! I'm still adjusting to how fast if heats up the pan.

Perhaps we should note that the heat we're talking about is actually "warmth". That is, the electronics themselves may get quite hot, but the air that cools it and is vented is not. It's not cooking temperature heat. It's not even Death Valley heat. It's just too hot for the electronics and a fan and airspace are well less expensive than other thermal shielding.

This post was edited by plllog on Sun, Oct 26, 14 at 23:09

Appreciate all the information...you folks are great. It may be that my old radiant which needs a $400 control module replacement actually is dying because of the heat being trapped around it in the metal box. Before I install the new induction I'm going to cut openings in the kickspace area at the bottom of the cabinet and openings in the upper cabinet side wall into the adjacent microwave cavity which is open to the kitchen. Figure this will allow at least some passive ventilation. The cabinet the induction will sit on holds a lot of air but we have three drawers in it although there is a 3" gap between the end of the drawers and the cabinet back wall which should allow my passive ventilation idea to work. It's in an island so I can also cut openings top and bottom into the cabinets on the other side and back which should allow considerable passive ventilation. Saw on another post that someone was recommending a small low voltage fan to draw warm air out of the cabinet...it would kick on if the air in the cabinet gets above a certain temp. Guess I can always go to that if I need to.

I have a Bosch induction and I had my cabinet guy build a fully operational drawer that tapers down along the sides as it goes towards the back of the cabinet to accommodate the cooktop's metal box and the little flap. I only keep spices in front of the drawer and some measuring spoons and nothing in the back (although I bet some knives laid flat would fit just fine). It has worked really well so far.

Jim, that three inch gap behind the drawers is exactly the kind of channel recommended by many of the manufacturers for cooling the cooktop. Check your model's instructions for whether you also need a heat shield underneath. Your ideas for venting should work fine. I only have the channel, and my heat shield is very close to the cooktop (per instructions), and it's only an issue when I have a large mass cooking on boost, and/or for many many hours. Then, opening a drawer is a good, low tech solution.

I’m in the process of installing a 24in induction cooktop over 30in wall oven (installed under counter). i left a 1.5in slot air gap above my oven (right undet the counter) to serve as the vent source. im trying to find a vent cover so it looks deliberate intead of like a measuring mistake. I havent hooked anything up yet. so I don’t know if that air slot is enough to keep the cooktop electonics cool. i bought some kind of linear slot vent for a microwave drawer in hope that it will serve my same purpose. (seems to be correct dimensions), so ill find oit when it arrives. Has anyone come up with an elegant solution for this issue?

Here is the photo of the air gap i left above the oven that im trying to cover with a linear vent cover. Unfortunately the hole in the counter is slightky too small due to incorrect product literature on cuttour dimensions that didnt account for some screws on the cooktop (another problem to solve)