Interesting about the microwave as I have never seen one vented to anything.

We installed a vent hood into a 35-year old house that we bought in which the PO had installed an island cooktop. It also was also a colonial style home with bedrooms above the kitchen. It involved putting just one 90-degree elbow in the ceiling, and we ran the duct ran through the kitchen ceiling, it vented to the outside wall of the house. It made a huge difference -- before that the house always smelled like last night's dinner (even our coats were picking up odors). After it was installed, you couldn't ever smell a thing even when cooking (loved that!). Maybe not everyone needs this, but we like to use a lot of spices and indoor grilling (produce a lot of smoke) so it was an absolute must for us. Here's a before and after:

Function_First: Did you have any issues with permits or code with regards to bedrooms being above the kitchen? You must have also been lucky with the direction of the joists above the cooktop, right? Did you need to install a blower/fan into the ducting?

No, we didn’t have any issues, and we did get lucky that the joists ran the right way, and the only thing we had to move was a plumbing vent. This one does not have a remote blower, the blower is part of the hood.

MW are not ever proper venting so forget that right now. As for venting in a 2 storey house that will depend on many things We vented a hood through a closet in our 1905 1 1/2 storey house it worked perfect straight line up to the roof . If this is that important to you then you need to see the actul plans of the house you are planning on buying. IMO if at all possible the range on an outside wall and vented directtly out that wall is still IMO the best solution. You need to decide what is the most important.

homechef59 -- sorry you're having a bad experience. We currently have an island gas cooktop with a Zephyr island hood and are VERY happy with the setup. We know that downdrafts are generally not much good at removing smoke and odor, especially the foods we like to cook -- that's why the 2 story homes we're seeing are problematic UNLESS we can install an over island hood vent.

function_first Thanks for posting that idea. I have a one story but don't want to punch trough the clay roof for a vent. There's a vent already that I do not use 90 degrees away. Also my kitchen is interior , my range wall is in front of my bedroom closet

The right kitchen designer and contractor partner can vent anything. Sometimes it needs out of the box thinking.

And for the right price, anything can be done ;-)

Susan, you aren't supposed to vent into an attic space. it's against code. the vent needs to vent to outside.

Micros are one of the worst for venting. they work, but barely.

you will need to look for a venting/duct system that is carried outside. all diff types of hood vents. I got one for less than 800, it has 4 speeds, easy to clean and works great.

and an inspector will be able to answer the questions about the house. it's his job to make sure things are properly vented. just keep that in mind when it comes time to sell yours. if it vents into the attic and they catch it (actually, you really should advise the new owners since it's a fire hazard) you may have to change it

Right -- I should explain fully that we're not venting INTO the attic but ducting up through the attic and out the roof in a pretty straight line. I've been under the impression that we couldn't run cooktop ducting up through floors that had bedroom spaces but it sounds like that's not correct. I also understand the physics of not having too many 90 degree turns in the ducting which is what we'd potentially be looking at if going up through the first floor ceiling then in between joists. We agree about MW venting, even if it does vent to the outside -- it's just not heavy duty enough for the kind of food we like to make

ok good.

where is the nearest exterior wall in relation to the stove? not getting why it has to go upstairs, to an attic and then out the roof. is the kitchen in the middle of the room w/no walls?

if you find a kitchen w/an exterior wall, I'd get the super exhaust fan of your choosing and modify it to vent outside.

micros can be moved, hopefully.