The 2 factors to keep in mind are depth and total capture space. Make sure the hoods are at least 24" deep to get max coverage. Also making the hood 54" will make it more effective.

The only difference with an 18" high hood is that there is usually more capture space as the filters are tilted more or set further into the hood

What Joe said.

Other points: Wider is necessary to capture the effluent expanding as it rises; 54 inches is a good nominal value for a 48-inch range, and should be sufficient for operation in the 33 - 36-inch above the counter regime. Front to back depth should also provide similar overlap within the limits of practicality. Choosing which burners to use for what cooking may influence the perfection of grease and odor capture and containment.

Use of a side-view stick-figure drawing will reveal both head clearance when bending forward and sight line adequacy.

Actual flow rate should be around 90 CFM per square foot of hood aperture. Use a factor of 1.5X greater flow rate blower rating to account for pressure losses.

Make-up air is also a big deal at these flow rates, and this is a topic you will need to review here on the Appliance forum and on-line at various sites that will be revealed by a search.

kas

If you are 5'7" I think you may eventually regret putting the hood at 29" above the counter (5'5" above the floor). We had a hood in our old house that was 2" lower than my height and I hit my head on it many times. If you are 5'7" I'd put the hood at 32" or higher so that it clears your heads. There are a lot of tradeoffs in hood design; I'm not a fan of concussions so this one is near the top for me. You may have different priorities.

Thanks Joe and Kaseki.

The 24" depth seems to be a limiting factor. You're pretty much looking at an 18" height with zero options for built in. But as I said, I cook a lot of peppers, a lot of fragrant things and I don't want to stink up the place.

If I went with a 22" depth hood am I really going to have to be using the back burners for any of those more effervescent cooking jobs? What about the charbroiler, will I need to be using the back half of it? If so, this makes my choice easier.

Along the same lines, if I went with a 24" deep but kept it to 48" wide (Storage space is at an extreme premium in this home), will I be ok, or am I going to have people running out the house when I'm cooking/running risk of smoke alarm (which scares the dogs to no end)?

Kaseki: Thanks for the input on the make up duct. I honestly have no idea if my last home had one installed. I would hope so, but I wouldn't be shocked to find out that it wasn't. Looks like you have yours down a hallway, are there limits to just how far away it could be? How about the opposite, can it be right next to the hood? A vent infront of it with the unit up above? We share walls with both neighbors, so going out that way won't work, and below the kitchen is the entrance to the home (which will soon have a door closing it. There is a skylight that can be left "open," but I can't be sure it always would be).

Stan: Thank you for that. I remember we set the island one to 6'1" for that very reason (as both our fathers are that tall). If it's going to come out 24" I will definitely want it higher than my height. It's interesting that Best recommends 24-30" above and Wolf recommends 30 to 36". If we do one that is 24" deep we'll likely put it in the 34-36" range. I definitely don't want to feel crowded.

You are the first post I have seen with a wolf 48 inch with a grill. Could you please tell me your thoughts? I want to buy that exact model and cooked with the grill at the wolf store and loved it but everyone on houzz keeps saying not to ever put a grill in your house but I'd like to hear from someone who actually owns one! Help-need to finalize this week. It was my favorite thing on any appliance I've tried!

"everyone on houzz keeps saying not to ever put a grill in your house"

Ethancremepie - just to be clear, on your other thread only one person told you not to get a grill. The rest of the posts were about what would be needed in the way of a hood for a 48" range with grill - because that is what you asked about. You want 1200 cfms, so we told you about required makeup air. We told you about the ductwork required. You want it to be quiet, so we told you that would be impossible with 1200 cfms unless you spend more on an external blower. You said you wanted to know if VAH was worth the extra dollars, so we told you that it might be more difficult to clean, and a poster explained his/her opinion on VAH.

"You are the first post I have seen with a wolf 48 inch with a grill."

On your other thread someone wrote a long post about his/her 48" rangetop with grill. Another took the time to search for a previous thread for you to read which compared the VAH hood with a baffle filter hood. You ignored all of these, and didn't respond to any of these points that people took the time to provide.

Wow you clearly seem offended and not sure why. I appreciated all of the input and took all of it to heart in my decision making. I wasn't just referring to this thread when I made the statement "everyone keeps telling me". 3 separate salespeople at appliance stores, 99% of every thing I found on the internet in months of searching ranges and range hoods, and 99% of every post I could find related to this subject on house spending hours a day searching for the past 6 months. I was not exaggerating when I say everyone. I was trying to not be too wordy in my post. I took in to account all the technical points people were making, but finding someone who actually has the grill I want in their house and it's functioning the way I want it to was invaluable as they are the only ones I've run across that could offer advice after using the actual product I am speaking of. Although educated opinions were given, none of these people used the specific grill I am speaking of therefore could only give a best guess. I like to research and have all the information possible to make the best decision so of course finding a person who has the grill I want offers me more information on top of all of the technical perspective to help me make a more informative choice.