The wok will generate a rising effluent velocity of around 3 feet per second, or 180 feet per minute. If the hood aperture is 3 ft x 2 ft or 6 square feet, and the actual air flow really were 600 cfm, the air velocity would average 100 feet per minute over the aperture. If the hood aperture uses a mesh filter at the aperture, the first bounce of the rising effluent off the mesh will be downward and not all of it will be immediately captured, much less contained. With a "pro-style" hood or commercial hood, the first bounce of the effluent is generally upward toward the baffles where the local velocity is rising while the upward momentum of the effluent is falling. In such a case the actual air velocity can surpass the effluent velocity after the next bounce and containment is achieved, even for that part of the effluent that bounces off the baffle surface. In other words, the adequacy of a given cfm in an application will depend on a lot of factors, and one of them is the hood design. For noise, it would be best to compare the hoods in operation. Applications where a remote blower can be used, particularly with enough duct length and space to add an in-line sound suppressor, will be quieter than applications where the blower is in the hood, due to suppression of blade tip noise, assuming similar fan designs. kas

The crux here is that you believe that all 36" ranges cost $5000. As Clooney mentioned, I just checked on AJ Madison and there are several 36" gas ranges for well under that, for example a beautiful Bertazzoni for $3000. Also, there are some people on the Appliances Forum who love their NXR ranges, also $3000. I am assuming you are looking at an all-gas range. If you are looking at Dual Fuel, you will pay up for that. But IMHO, a dual fuel upcharge is not worth it. There are more electronics to break, and the idea that a gas oven is not as good as an electric oven is outmoded. I would not, if I were you, trade down from a 36" range to a 30" range. Also, since you said there are built-in cabinets above the range, what about the cabinets on either side of the range? Are those base cabinets staying, so that you are going to have to add something to fill in the 6" if you go from 36" range to 30" range?

Ideally the hood should be 6" wider than the range. I think the recommendation above to go 12" wider than a 30" range is overkill. "reasoning was something along the lines that with a bigger hood, you can install it a little taller (looks better) than the recommended distance between stove top and base of hood." Either you misinterpreted what you read, or the person who said that is misinformed. I think what you are referring to is that a taller canopy-style hood will gather and contain, i.e., capture, the smoke and grease better than a more sleek-looking flat glass hood for example, or the smaller undercabinet hoods that are 3-6" tall. In addition, a taller hood has more of a wow factor and presence in a kitchen. I would not equate a taller hood to being able to install the hood a greater distance above the range. Also if you install a hood too high above the range, the proportion can begin to look odd. Most of all, installing the hood too high above the range gives the smoke and grease more opportunity to escape. You wouldn't want to spend all that money on a hood and then curtail its efficiency by installing it too high. The ideal height is a 30-36" distance between the top of the cooktop and the bottom of the hood. I didn't see any mention in the OP of exhaust duct size. Duct size is important. You could buy the best hood in the universe, but if the duct is not sized appropriately, the hood will have decreased efficiency and increased noise through no fault of its own. The most common required duct diameters are 8" and 10". The hood's specs will say which. For a 30" range, the 36" hood will most likely require an 8" diameter duct. Hoods that require a 10" duct typically are for 48" ranges or larger. Do NOT give in to your builder if he says "I am sure a 6" duct will be fine". That might be an easier installation for him, but you have to live with it.

Want a quiet, high quality range hood. Seems like the prices are all over the place and the reviews seem to vary a lot as well.