Venting experts - can you vent through the roof?
My friend bought a house that needs a lot of work before she moves in. She's not doing the whole kitchen, but the OTR microwave doesn't work, so she's going to put in a recirculating hood with a charcoal filter. When I looked askance at that, she said she doesn't cook much at all, mainly pasta or stir fried vegs (she's vegetarian). She had a gas line run so she could replace the electric radiant range with gas - not commercial, just a regular gas stove.(I suggested she might like induction, which no one had ever mentioned to her. If she doesn't cook much, why did she need a gas stove instead of the electric anyway?) Her GC assured her that it would be fine for the cooking she does. So first, will it be fine? With a recirculating hood, would she be better off with induction than gas, or does it not really matter?
Someday, she might be able to move the range to the outside wall and have a real hood, although the outside wall also has a lot of windows. But when I suggested that they could also take the vent up through the high, cathedralish ceiling - the kitchen is on the top floor - her GC said that you shouldn't do that because you should avoid making openings in the roof.
I thought I'd read on here about people venting straight up. So, is it OK to go through the roof or not?