I believe some places have codes concerning the vents, so you might want to check on that. I had a GE Profile, freestanding gas range with center burner / griddle and I had it vented with an over the range microwave. It was not adequate ventilation and it was one awfully hot kitchen. Make sure the vent you get can handle the BTU's of your gas range.

Sorry I can't help more with the 30" size question.

You can't have wood directly over the stove. It's a fire hazard. If you must go with a 30" hood, it should be stainless. And it would be fine to have the cabinets next to it touch, but it will be more difficult to clean as a tradeoff. If you want a wood hood, it should be 36" wide and 27" deep, wiht only the metal insert actually directly above the range.

Hi debbie2. Nice that you're so close to your mom so you can help. :)

In preparation for our kitchen upgrade, I came across the 2009 International Residential Code regarding cooktops, combustibles and vents.

Range Cooktops:
-Combustibles installed not less than 24" from open top broiler. See manufacturers instructions.
-Distance above top of cooktop to unprotected combustible material not less than 30"
-Clearance to adjacent combustible surfaces per the manufacturers installation instructions

I think it's the third 2009 IRC cooktop guideline which indirectly addresses the 3" additional clearance to adjacent combustible surfaces (wood cabinet edge) on each side: almost every manufacturer I've checked specs on includes that extra 3" to side rule. Many mention voiding of warranty if not implemented. A stainless vent hood would not modify that extra 3", as it's pertaining to the cooktop surface if the cooktop manufacturers so require.

Hope this helps.
Our town code office has its code and the state codes: as I understand it, 41 states have incorporated the 2009 IRC.

I've bookmarked this thread to come back to when we get closer to that part of the remodel. I too have a 30" range top and currently a 30" space over it. I don't see any way of changing the size over the stove for a larger vent hood and I really wanted a wood hood.

If you look at the specs for your mom's GE range, I'm pretty sure you'll find it doesn't need any additional clearance to the upper cabinets.

debbie, those IRC 2009 guidelines are guidelines. Do you know if your town even requires venting of residential units? Mine doesn't for example. Only thing they suggest is that 30 inch to top of vent hood, but no side set back is necessary, heck no venting is coded.

As to the manufacturers, if your mom's unit is brand new, then the specs guidelines may be worthy for warranty. But warranties expire on most appliances within a year, possibly two. There are options.

Fire hazard is a main point: good idea to keep a red fire extinguisher in one's kitchen, made to extinguish most types of kitchen fires. Grease fires I think are D units though (i.e., separate type).

Here is a link that might be useful: Great GW link: Wall Hoods for Wok Cooking

Thank you everyone for all your posts and wonderful information. I relayed everything each of you wrote back to my parents. Our cabinet designer did help solve the delimma of wood versus stainless steel. Once we heard the price of the wood hood, they knew they had to go with the stainless steel hood. And with everyones feedback, they have decided to go with the smaller upper cabinets to allow for the 36" hood. They don't cook elaborately with woks and other fancy cookware, but the information regarding the noise and BTUs, and views on which looks better helped greatly in deciding on the 36" versus the 30". Thank you again each and every one. You helped make the decision so much easier.