The very FIRST question you need to answer is how are you going to cook ? That is the single most defining piece of info that you need to answer. If you boil water for pasta and heat soup and use sauces from a jar then yes you will get by with the least cfm's . If on the other hand you are going to do high heat stir fry and high heat cast iron griddle cooking ex. steaks then you need WAY more cfms. You need to also understand how the cfms work. The distance to the outside of the home...also known as the duct run plays an important part...longer = more cfm to compensate. I have my hood at 33" cause I hate a low hood...I have 1400 remote blower to compensate. I have my hood at exactly 54" wide which is the same as my cooking surfaces...note high cfm to compensate. I get perfect capture due to the high cfm.You want your hood deep enough from front to back to cover the whole cooking area...I don't know who would say you don't need that but they are very wrong. You also need to understand that you do not want to have to use your hood on high. You want the low/med setting to be sufficient. The reason for this is that the higher the setting you use the greater turbulence is created inside the duct work...the air which includes the odors and steam etc ( aka HOGS) come back at you so you want to always have more than you need. You will also get better use of your hood if you turn it on approx 5 min before you ever start to cook and let it run for 10 min after you are finished...also remove all pots etc from the heat to stop the odors after cooking. This clears the duct work at the end and gets the air flowing at the beginning. If I can answer any other questions please ask. If you go over to the Kitchen Forum you will see a thread posted by sabjimata on high heat/grill cooking...I have posted pics on the thread of my set up in use. It is still on page one so you can easily locate the thread. Good Luck and ask lots of questions before you buy...I spent a YEAR studying this before I bought my set up. c

1) Make sure your carpenter makes the wood surround / hood bigger than the sizes of the insert. so if your insert is 34" x 22" make the hood 36" x 24" ish if possible or even bigger. 2) Recess the insert 6" up into the cabinetry to create a larger capture area. Think of this as an upside down sink, the insert is the plug hole and the bowl is the wooden frame. The bigger the frame the more smoke and grease will end up going out of the house. 3) Insulate the gap between the wood and the insert. 4) If possible make 2 x 45 degree turns above the hood instead of 1 x 90 degree turn, this will reduce noise and friction.

Lest I sound like the craziest mother on the planet for the timing of this move. We discussed and encouraged DS to take a gap year and either travel with us, or go off on his own (this is not a new idea for him- I have always liked the concept and encouraged him to consider it before) the answer from him has always been the same though- no thank you. DS is in a huge rush to become an engineer- he was born that way. Also, I had always encouraged DS to go to school on the East Coast. This idea had very little to no appeal to him. DS loves traveling the world, but when it comes to the US, he loves Northern California best of all. East Coast schools were back ups should he not have gotten into his first choice (which he was admitted to early decision.) We have kept the house in the very same town DS will go to school in and it will be occupied by our housekeeper and our cockatiel. In addition I am planning on having the kitchen remodeled, so I will have an excuse to visit every month. However, I am very sure I am not the person he will be missing the most- that distinction will be held by DS2 who is only one year behind and working very hard to get into the same school. Frosh orientation begins Spt. 19. The brothers (DS 2-4) have a two week fall break around Halloween, so perhaps a long weekend in SF could be arranged- if that seems like a good idea we could absolutely do that. And then we will spend Thanksgiving in NYC all together- and then there are three weeks for Christmas and so on and so forth. The last mitigating circumstance is that DS has a very close relationship with a professor at the school already - I am pretty sure they will see each other at least weekly at Mass (this prof. was DS's Confirmation sponsor.) Thank you so much sheesh and Kim for your kind and thoughtful feedback. Kim, I am very grateful to you for your offer of help.

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.