In our new house our final kitchen is a few years away (we'll start with a temp kitchen). If possible, I would like to settle and install ducting for the stove/range before we close up the drywall.

Lifestyle: I very rarely cook meat or use oil, so little in the way of grease or smoke issues. But I do cook soups, veggie chillie and tomato sauce that simmer for a long time and make a fair amount of steam. And my husband's favorite veggie is brussel spouts which sure can leave a lingering stink in our current house. ;-)

Proposed Equip: Induction stove top, electric oven, standard (30"?) size. No gas, no grills or anything like that. We've installed an HRV and have an exhaust vent located in the kitchen area (not too close to the stove) and a fresh air supply in the living area (open floor plan).

Recirc or Vent Outside?: Given lifestyle and HRV, do you think a recirc range hood is acceptable? (see duct difficulty below)

Ducting if Venting Outside: The stove/range location is on an outside wall, but on the other side of this wall is a screened in porch with a metal roof. The framer said just punch through the wall with vent in the porch area. Really? Is that OK?
Also, I did some very initial research on range hood vents and saw duct sizes like 7" in diameter - Wow, that's a lot bigger than I was thinking. I believe I was looking at a standard GE hood vent, but I have to do more research. For just a standard vent size (not the commercial ones that can suck up a small child) - what are typical duct sizes?
Would I need to buy the exact range hood I want to "rough in" the ducting (are they that specific, or are they pretty generic)?

Thanks for your help!

In an airtight house you definitely should have a vent to the outside over the stove. I am amazed out how much I REALLY need mine. The one I got goes up to 600 cfm (3 settings) and there are times I need that 600 cfm, though for the most part use it on med or low. If I had known just how noisy it would be I might have gone for something that had a better sone rating, mine (An Air King Grenada) is very noisy.

I think venting into the porch is a really bad idea. You can punch through and put the exterior ducting in the porch, but you should probably then go up though the porch roof and finish it off properly.

As to size, mine has a 6 inch duct. They vary widely. There are many models on the market, so once you figure out what you need (cfm, sone rating, style, size, eStar rating etc) you should be able to find a model that meets your needs.

-Rosalinda