No, at least in my opinion.

It does not work for comedic cooking.

The improvements have been marginal.

This post was edited by deeageaux on Tue, Aug 27, 13 at 22:37

...another no to the downdraft, especially Jenn-aire!. we had a Thermador pop up downdraft , and it worked OK, but if you're stuck with the island set up, as we were, can you put an island hood above? I put an island hood above our new Bluestar range and it works great!

Ctycdm, that's already what I'm thinking. How did you run the ductwork? For me, If I go straight up, it would have to go along a bedroom wall in the floor above, or horizontally along the kitchen ceiling.

We were fortunate to have a single story, and vent right up through the roof. You can go horizontally in the space between floors to an outside wall, or up another wall to a roof above, although that can get complicated with duct sizing, you may need to build a chase to enclose....

When one is cooking with high heat, the uprising effluent velocity can be 3 ft/s. When this is intercepted by an overhanging hood, it is feasible to capture and contain it with modest air flow rates (90 cfm/ft^2 with baffles).

However, when using a downdraft aperture at the back of the cooking surface, capture and containment would have to start with redirecting the effluent momentum from rising to horizontal motion at the aperture. This requires at least as much transverse velocity at the effluent as the effluent has (causing a curving trajectory). However, air velocity outside of a duct drops rapidly with distance, meaning that for full capture of effluent from the front burners using a downdraft aperture the size of the cooktop, the air velocity at the entrance to the downdraft system might have to approach ten times that of the effluent.

30 ft/s is 20 mph close to the mesh, and maybe 40 mph through the mesh gaps, so one can imagine that the noise level might be a tad higher than desirable. Hot greasy cooking only on back burners might reduce the ten times factor to three times, so a large exhaust blower that could handle the restrictions (pressure losses) of a downdraft system might be effective, albeit still somewhat noisy.

To the extent that they are cost and aesthetically feasible, hoods approximating commercial units will be more effective than hoods that greatly diverge from this pattern.

kas

I have a JA downdraft range (maybe from the '90s?). It's not great but it works okay. I think this is because it's not ducted at all and just vents into the crawl space.

A real hood can be installed in just about any kitchen if you're willing to put in the effort. (Condos and apartments are the obvious exceptions.)

I would not rule out a house based on a downdraft (I guess that's clear). Maybe it needs a little remodeling anyway? :)

We had a Jenn Air electric smooth top cooktop with the downdraft in the center. Cooktop is in an island with venting to the outside. Made lots of noise, but was totally useless. Had to cook bacon outside unless I wanted to live with the aroma for days.

Remodeled last year and replaced with Bosch telescoping downdraft. My expectations were low based on the old Jenn Air, but it is wonderful - no more cooking bacon outside!

I had one of those new-ish Jenn Airs in my house when we moved in. Not only would it not suck smoke/steam from the top of the cooking surface well, it would suck heat, as in pull the flame away from the bottom of the pot. If the fan was on I could not boil a pot of water on the anemic sub 10K open burners they provided. When the left hand unit is on (grill/griddle/more burners), the fan was always forced on, so I had no choice but to wait to boil water.... It was in fact COMEDIC, but it was not cooking, so I do not refute deegaux's comment.
Its not as much work as you might think to relocate a cooktop/range to an external wall, usually gas and electrical lines can be run through the subfloor easily. Plumbing, as in switching places with a sink, on the other hand, can be a bear.
If you love the place, look at the bones of the kitchen to see if you can get exactly what you want eventually without knocking down walls.
But no, just swapping out an old JennAir for a new one would be a major party foul if you were here looking for advice.

I have owned two Jenn-Air down draft ranges (1993 - present) and cook a lot! Now that the keypad will not work, etc I'm switching to an updraft. I do not recommend ventless at all! I'm not going through my metal roof, so my HVAC is creating a slight angle, exiting the side just below roof. Get a really good contractor and HVAC! It can work but a good one will not create too many angles (grease/ fire hazard). As for updraft, find a reputable dealer (not places like Lowe's) who will explain sones/cfm, etc. Mine will have 600-900 cfm.