clinresga: Thanks for all the info and good things to think about. I am glad to hear that you like the Fantech silencer. Our attic should easily be able to accomodate its size. Do you know if they reduce the effective CFM of the blower? (I hope to get off another project today and start calling various companies to figure out what we need). We will be using a custom surround - truly custom in the sense that our contractor/finisher will make it for us in any fashion we want. We haven't yet settled on a specific design, but it will be made of wood, painted the wall color and we'll probably try to make it "disappear" as much as possible. Ha! Given the nature of this project (restoring a 1920's remote fishing resort - off the grid and way in the middle of nowhere), we are working with a contractor who does beautiful work and can pretty much make anything out of any material. (You should see the cabinets he's made that look like they've always been there, the rock fireplace surround he built that is a deadringer for the 1924 one that came off in the 1970s, etc. He is a true artisan.) So for the range hood, we are constrained by the location of the refrigerator on the one side, and the size/depth of the range. I believe we will have a maximum of 43-44" for the surround (the stove is 40" wide and sits about 32" off the wall). It sounds like MA might be my first call if they can make a custom liner that is the right width and extra deep. We did hear back from the stove restorer, and the burners have a total of 72K BTUs (12K each) and the ovens have a total of 40K BTUs (20K each). I still think the FDK10 will work for us if we get to that level of pinching pennies, but we'll have to run the numbers to see! In another post, I saw you mention that you have a wall control for the blower and lights. Did that come with the MA? Or is it manufactured by another company? Are the blower and light controls on the same unit?

Hi. I've been looking for hoods as well in your price range and keep coming across Kobe. Doing a search on this site I found mostly positive things, though I did find this thread (http://ths.gardenweb.com/forums/load/appl/msg0509233413885.html) that deals with a problem with grease leaks. There is also at least one mention of the fact that, at least on one model, the lights in the front under the hood means that the suction for the front burners is not so great because the part that takes in the smoke and grease is set farther back. As to the Zephyr, I've also come across good things except for the price. These seem to be more expensive than the Kobe. Can you tell me which models of both you are looking at and where you are looking to purchase them from? I'll be following this thread closely, as I want to by the hood soon. Any info you find out would be greatly appreciated. thanks, tim

See the thread linked to below. Far more important than a rated (absolute, in a lab) CFM number is the placement, size, shape of the air movement obstacles like walls and cabinets, and of the hood compared to the range: you want greasy smoke to go into the hood and not to spread out into the kitchen and beyond. Greasy smoke is made of fine particles that may not rise much unless "directed to do so". In threads I have read here in the archives, 600 CFM is considered large and plenty and good and sufficient, not undersized in any way. Ultimately it comes down to Other Factors, not CFM. The physical dimensions as mentioned above are the biggest. 2ndly : Your makeup air or lack of it. A fan can turn turn and turn, uselessly, without pushing as much air as expected, since it has to push against resistance from your own house air holding itself IN. Air is not infinitely compressible or expandable, far from it, actually the opposite, although air can be compressed (with great force) it's not compressible-expandable in a non-pressurized environment (i.e. your house), it's like any old fluid, like water in a straw, that needs to be replenished from one end if you pull some of it out of your house. That's why fireplaces don't work well until there is a source of new air coming in to replace the air going up the flue. For all intents and purposes air is not compressible (or expandable) so think a lot about this and plan for your air to Come From Somewhere. Air movement. Air path. Air flow. 3rdly: Your duct size may be a physical limit too. Kobe products work on small ducts so here you are "in luck"; you chose a good one. Once you have a handle on your hood's local-space configuration (barriers preventing smoke from spreading) and air movement path into the kitchen, then putting a rated 600 CFM fan in that space will be fine fine fine. The thread below contains a link to another thread in one of its first posts, and that thread then also contains a link to another thread in one of its first posts too, and then again a couple times more. Sounds like a fractal or infinite series, but it does stop. HTH -david Here is a link that might be useful: First of several, re: Sizing a Hood (CFM) and Other Factors

Well, I can be long and rambly too, and suggest reviewing the many hood threads here to see that demonstrated. I can also suggest that if you, @Margaret Davis, do so, you will learn a lot more about both hood requirements and make-up air (MUA) requirements. I'll supplement the information on this site, first by noting my astonishment that whoever wrote that blurb for Proline seems to be missing the most fundamental concept -- no air leaves the kitchen that doesn't get replaced. No reports of imploded houses due to hood blowers pulling a vacuum have ever come to my notice. With respect to the requirement that outgoing air be matched by incoming air, the size of the kitchen is irrelevant. The blower size is irrelevant. How long you run your hood is irrelevant. There is always a balance such that the actual hood duct airflow matches what leaks into the house, or is allowed to flow into the house, or is deliberately blown into the house. Gag the MUA, and the house interior pressure drops until the hood blower volumetric flow rate matches what can leak in at that pressure drop. The controlling aspect is the 'fan curve' of the hood blower when MUA is passive (not blown) and the combination of fan curves when the MUA is active (blown). Example fan curve [click to enlarge] Broan 1200 CFM blower fan curve. The pressure that determines where one can operate on the fan curve is determined by pressure loss passing the hood baffles, the ducting, the exterior cap if not included in the fan curve, and the MUA pressure loss getting air back into the kitchen. With a large diameter passive MUA or imperfectly tuned active MUA, you are likely to see the actual hood air flow to be only 2/3 of the zero static pressure flow rate, that is, 2/3 of 1200 or 800 CFM. Modern codes require, as @Celedon noted, deliberate (active or passive) MUA when the hood rated blower size (not actual flow rate) exceeds 400 CFM. This is to ensure that any combustion appliances that are present, or may be present in the future, are not back-drafted by negative house pressure thereby introducing carbon monoxide into the house. Second, I won't go into hood requirements here as those should be easily found among the hood threads, and in any case you seem to have picked a hood or hood size. However, I will address the vertical duct question. Generally, the highest pressure losses will be the hood baffles and the MUA if passive, depending on duct size and filtering. So longer ducts will drop the overall flow, but perhaps not too much relative to these causes. This can be evaluated by plugging the duct parameters into on-line calculators that may be found by searching. Third, most ventilation noise is air turbulence noise, dominated by that at the blade tips of the blower. Duct turbulence will also contribute. Silencers reduce this, and may (as in the case for me) reduce the noise such that baffle turbulence (hiss) dominates. An advantage of running the duct into the attic would be that in the attic there may be room for a silencer to be inserted between the external blower and the hood. One can also angle the ducting there so that the external blower is at an advantageous point on the roof. No matter what tortuous path you choose, and the ducts you have sketched aren't really that long, be sure that the chase allows access to the ducting in case cleaning is needed (usually rare in residential cooking). In cold climates it is best to keep the duct warm over as much length as possible, so exterior ducting may want to be in a chase if very long. With a larger chase, a silencer can be put closer to the hood, which helps suppress duct noise. Fire protection in the chase may be an issue; discuss with your code enforcement officer. You should plan on using at least 10-inch ducting, but note that the Fantech 10-inch duct silencer is 14 inches in diameter by 3 ft long.