Why not post photos of your kitchen? Location of your cooktop and the built in ovens might require a major reworking of your kitchen cabinetry to accommodate a range. Simple replacement of a microwave/oven combo unit required the rebuilding of my cabinetry. Perhaps there is another solution for you?

Hi ptreckel,

Thanks for suggesting I upload some photos. I've done so now. Yes the more I consider options it's looking like it's more of a kitchen re-work than just appliance replacement. (big sigh...)

I'd live with this for now until you're ready to do a full remodel. The whole plan needs to be reworked and replacing one appliance that's still mostly working doesn't seem to make sense if the ultimate goal is to redo the whole thing.

Have you looked in the cabinet above the cooktop to see if there is an old exhaust duct? if there is, take a look in the attic to see if the duct goes through to the exterior.

Thanks Sabrina 

Yes looking that way.  We've been thinking about remodel for awhile. Unfortunately we can't really live with it for now because ovens HAVE to be replaced. 

Lomo,  I  hadn't thought of the safety aspect.  Another good point.

Apple pie,

The jennair downdraft cooktop is vented to the outside through ductwork underneath.

I'm learning the problem is that finding replacements that have same ductwork configuration is challenging if not impossible. 

If we do decide to go with range hood option. That means installing ductwork for it.  Possible because kitchen has accessible attic space above.

I think we need a few more pics of the space please . Here in comments. I see a very dated kitchen so maybe tell us a bit about the plans for the future. Downdrafts are IMO pretty bad for venting But I need to see the whole room and then make suggestions.