lamermaid: Great points, and a great ongoing conversation. I have been perhaps overly repetitive in my opinions about VAH hoods. Like others (keitel comes to mind, especially as his (her?) "My Ventahood drives me insane" thread has recently been resurrected), what makes me crazy are the large number of posters who automatically suggest VAH as the "best" option whenever a ventilation request is posted. In particular, I am struck by how many folks who tout VAH's do so based on one of two things: 1) "the salesman at my appliance store says VAH is the best and that the [fill in the blank] hood is inferior because of..... (failing to mention that it's the only brand of hoods he sells) or 2) "I have one and I think it's great" (posted by someone who has never had a hood other than a VAH to compare to). In contrast, you are someone with personal experience with more than one brand and style of hood. Thus, your opinion counts, in my mind, much more. And I do believe that much of the advantage that I perceive in my hood is not so much from the fact that it's an MA, but rather than we have a remote blower and silencer, which I think is a wonderful setup. The reason I've been such an MA fan is the amazing customer support. I also love dealing with a small, American company that still actually manufactures here in the States (when I called to check on the status of my hood, the woman who answered literally ran back into the shop, found my hood under construction, spoke with guy building it, and came back with a hard estimate on completion--try that with VAH or Broan!). If I can buy a handcrafted, custom hood, which uses proven baffle technology, and which allows the use if desired of a remotely located blower, infinitely variable speed control, remote switching for lights and fan speed, etc, for the same price as a VAH--which if I'm not mistaken, requires the use of four separate squirrel cage blowers, each of which needs to be washed by hand, to achieve 1200 cfm, then I'm hard pressed to understand why the VAH would be a better choice. But.....as you've already pointed out, mine is an overly-obsessed opinion that everyone should take with multiple grains of salt. Having said that, we still love our Dacor PGM36 cooktop. It was my first experience with a modern, high performance cooktop and I still have lots of fun cooking on it. It's a great looking piece, still love the blue LED indicators on the knobs, and the 15K burner is more than adequate for my frequent searing etc. For that "space" (36'' five burner drop-in cooktop) I still can't see anything that would outdo it. The Lacanche is however at another level entirely. It's just a piece of art, classic, yet performs fabulously, with two 18K burners, two ovens, french top, etc etc. I do think it's a tougher question if you're limited to roughly 30'', and to only the one oven in the range, and I'd think hard about that choice--we also liked the Wolf and I'd be very happy, though not quite so passionate, if that was what we had gotten. Post questions to the longstanding LC thread.

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.

It might be easier to think of this hood as being comprised of two assemblies. The outer assembly is made of wood parts rigidly bonded or otherwise attached together to generally resemble a cabinet without a base. The inner assembly (called a liner) is a metal shell that incorporates (hopefully) a set of baffles, light and motor controls, lights, and, optionally, a blower. The blower subassembly comprises a fan blade sub-assembly and a motor sub-assembly. Alternatively, if an external blower is used, then there is also a cover and damper as part of the blower assembly. I would not expect a typical cabinet maker to supply the liner assembly, but may want it on hand to fit to it. As I don't have one of these, I welcome any refinements of my description that may be needed.

No air leaves the kitchen that isn't replaced by some form of MUA, whether deliberate or house leakage. While code may draw a threshold at 400 CFM (rated), the actual CFM achieved without deliberate MUA is likely to be down in the 200 CFM region. For capture of cooking plumes driven by hot oil cooking (stir frying and searing), with plume velocities potentially over a meter per second, the specific flow rate should be upwards of 90 CFM per sq. ft. of hood entry aperture (the entire area) for common residential hoods. And this is actual CFM, provided by a blower that has been selected after accounting for pressure losses in the cooktop to outdoors back to cooktop loop. These include baffle, duct, and MUA pressure losses vs. the blower's "fan curve." See sketch. If you don't have any other combustion appliances, or have them but they have their own MUA and are thus not affected by kitchen air pressure, you may be able to size "passive" MUA (no blower) vs. candidate hood system blowers such that you can achieve the desired flow rate calculated from multiplying the hood entry aperture by 90 CFM/sq. ft. At a minimum passive MUA will have a filter pressure loss, a possible heater filter loss, some (maybe small) duct and diffuser pressure loss. With affected combustion appliances and without means to provide them MUA, then MUA for the hood system will require balanced pressure in the house and this will require that the MUA system have a blower. In general, determine requirements first and choose components second.