I am in the process of researching a range hood insert for a 30" dual fuel range. I will need 600 CFM's. It will be vented out of the back towards our driveway, so I do not want an external fan. Recommendations needed.

Reviewing the many kitchen ventilation topics on this site (hood, MUA, baffles, insert, etc. key search words) will help provide important background information. Also, it may let me not repeat myself more often than once a week. Limiting my comment here to a portion of your question, maximum quiet results from a roof mounted blower/fan, in-line silencer (e.g., Fantech), and a baffle style hood. This limits the sound at the cook to mostly turbulence noise around the baffles, and possibly a bit of residual low frequency rumble that the silencer can't attenuate. In my case, for example, I have the largest Wolf Pro Island hood (see the Wolf Design Guide) over an induction cooktop and an induction wok hob. It connects via 10-inch round duct to a Fantech silencer in my attic, that connects to a low profile Wolf (Broan) centrifugal roof fan. (Commercial style upblast units could also be used.) The blower rating is 1500 CFM, but pressure losses through the air paths likely limit it to 900 CFM. Air flow areal rate is about 90 CFM/square foot of hood aperture. To dampen any duct vibration, much of the duct has been wrapped with automotive door dampener material. Conversation at the hood at full blower power can be managed at normal voice levels. Wok sizzle is louder than the baffle noise. Cooking odor is fully captured and removed, as long as DW remembers to turn the blower on. kas

The hoods at the link appear to be 19 or 22 inches deep (front to back). Strive for as much front-to-back depth as available in your price range because it will improve capture of the rising and expanding cooking plume effluent. I'm not sure what "commercial style cooking" means, but unless the baffle pitch angle is greater than 45 degrees, the assembly is non-compliant with NFPA 90 for commercial installations. Lower angles typical of residential designs are fine for residential purposes. For a higher altitude view of the subject matter, you may wish to review my comments at: http://ths.gardenweb.com/discussions/3554712/advice-re-kitchen-hood-imperial-fantech?n=2 kas

I am the resident expert only because real HVAC systems engineers don't frequent this forum, as far as I know. Noise introduced into the kitchen will be significantly reduced if an external blower with silencer can be fitted. A lot of the high frequency blade tip turbulence caused noise will be removed. This is also true of an in-line (duct mounted) blower. The issue of the neighbor is difficult to assess. What is the configuration of his or her windows relative to your potential external blower (1500 CFM I assume you meant). Your own window sound transmission is also an unknown. Generally, the external noise could be abated by (a) using a silencer on each side of a duct mounted in-line blower, or (b), using a deliberately under-driven* "up-blast" commercial blower (mounted as a side blast). (I think opaone is using an under-driven blower for his new system.) It is also possible to use a chase to move the blower up to roof level. I have a 1500 CFM nominal Wolf (Broan) blower on my roof. Its sound level is detectable but not obtrusive from the ground, but it might be if in a wall location where the sound is "trapped" between two houses. Possibly a more expensive but similar in design Abbaka downslope unit would be marginally quieter. ------ * commercial blowers of this type can use a pulley system between motor and fan that allows for different ratios. By choosing a ratio that operates the fan blades below their rated speed when the motor is receiving maximum voltage, significant turbulence noise can be avoided. The physical cost is a larger unit than would otherwise be required for the desired flow rate. Residential blower fans are directly coupled to their motors.