Hi Gaby I would Love to have a 48" range!! The 36" is the maximum our corner would allow without major structural changes and I did not want to go there...however, in my dreams....a great range, George Clooney, etc. That being said....I am really happy with the efficiency of the hood. It does cover the front burners. I am training myself to remember to turn on the fan just before I turn on the range top....almost there! I would think that you will be happy with your hood as long as the cfms are adequate. Cheers Pam

In my experience with my 1400 cfm Tradewind liner with baffles there would be no need to ever "clean" any parts except the baffles. My rationale for this is the following. Once a week ( more often if it warrants it ) I remove the baffles and clean them. depending on how much stir fry and deep fat frying we have done they are quite greasy, sometimes very very oily and one or two times , before I realized that they capture everything they were dripping droplets of golden oil. I also wipe down the surrounding area and there is never anything on this area at all. I have pushed the damper up and tried to wipe in that area and felt up there with my hand and there is nothing up there either. The process of using your hood correctly should remove any need for cleaning other than the baffles. The hood should be turned on at least 5 min. before you begin cooking and remain on at least that long at the end. This insures that all grease products are trapped on the baffles and then the remaining products, steam/heat/odors are removed to the outdoors. I hope this helps you with your decision. The baffles or your mesh should be very dirty on a regular basis, depending on your cooking style. Also there should not be any grease on any part of your surrounding area in the kitchen. If there is then the vent is not working correctly or you can adjust your use of it. Good Luck c

I have a master bedroom closet area along a wall that is bisected by the chimney chase of a fireplace on the floor below, making a his and hers pair of closets. This is a triple-wall metal chimney surrounded by firecode sheetrock on the inside, studs, insulation, and sheetrock on the outside, including an access panel. It eats up about 30 inches of closet length. For a 10-inch kitchen hood duct with significantly less fire and access restrictions, you would probably loose at most only 20 inches. Many things are possible if the house design is recursively adjusted to accommodate all of the requirements. Do not rush the construction until you are certain that you have met your needs; there will be enough surprises even after everything seems to be defined. If you go to equivalent rectangular duct, you may still need to bulge the wall or otherwise ensure that there is not too much duct restriction. Rectangular ducts of equal sectional area to round ducts have a bit more pressure loss per foot. This should not be your first consideration, however, because you can find a blower with a fan curve suitable for the duct design, even if the duct path is tortuous. As for all of your construction questions, I'll have to ponder them when I have time, if I can understand them. In any case, if cooking is an important part of your life, then ensure that the kitchen design and the ventilation design are given the attention and space that they deserve. Unfortunately, it seems that your framing plan is somewhat past the point of easy revision. For others reading this: Please, please, PLEASE look into and solve all of the kitchen issues before finalizing a design and signing a contract. Comments on your bullet questions: - ?run horizontal through floor joists? YES - ?use rectangular duct vent when necessary? YES - ?Is it allowed to run near/along side the gas dryer vent? Not aware of any restriction on the moist air vent (note dryer vent has to be metal also. However, care to allow access for both, and particularly for the dryer vent duct for cleaning, is important.) For gas effluent vent, that should be determined by consultation with the architect, code officer, or gas company tech. Note: given a gas dryer, we are now in the regime of not letting the differential air pressure at the dryer fall below 0.03 inches, w.c., and make-up air performance or sealing off the gas dryer from the kitchen air is another big part of the kitchen ventilation design. - Run down into the basement if it can't run up? YES, but less optimal than up - Exit through an exterior wall rather than roof? YES - Best to get it in the garage and up into the attic and then up out the roof? Don't know about best yet, but it is a valid option. - best to have the range on wall A or wall B (does it make a difference)? TBD. Kitchen layout should account for numerous factors, of which duct location is only one. - assume need to use remote or in-line blower with any plan given its non-traditional route? In most cases, an external blower with an in-line silencer will be the lowest noise solution. kas

Ah. My apologies for abusive engineering descriptions. Sometimes I tend to unconsciously assume that all the previous stuff here has been read and digested, so all I have to do is present a reminder. Capture: The plume expands as it rises. The actual expansion angle is greater than 10 degrees outward, but ten degrees encompasses most of the higher velocity components for relevant cases. This means that the cone is wider the higher one measures above the pan base. At 36 inches hood height, for example, with a tangent of 10 degrees equal to 0.176, the plume has expanded outward by 36 inches times 0.176 or 6.4 inches. Similarly, for 30 inches, the plume has expanded by 30 times 0.176 = 5.3 inches. (Exactness is used here to clarify the calculation, not assert a defined boundary exists at the plume.) Suppose a pan base's maximum extent from the wall was 19 inches (which would be true of my induction cooktop if it were against a wall). Then one should aim for a hood aperture that was 19 + 6.375 = ~ 25 inches from the wall if 36 inches up. A 27-inch hood with lights in front of the aperture is close enough. Hence, your drawings have the angle going the wrong way. Imagine a really large traffic cone (without it weighted base). Slice it where it is the same diameter as the pan base and invert it over the pan. This inverted, truncated traffic cone, or rather a set of them perched on all the burners or hobs, can be imagined as defining the required boundary of the hood aperture. The desired hood aperture for good capture is independent of whether the structure of the hood is all metal or is metal inside of wood. Depending on your configuration, it may be best to space a smaller hood outwards and fill the gap at the wall side with some sheet metal. Side cabinets can help perform the function of side curtains in commercial configurations. (Note re pillog's comment. There is a small zone of high flow rate at the edges of the hood, and this has the effect of a slight increase in effective aperture.) Containment: Your analysis is correct. If the aperture is 6 sq. ft., then the desirable actual flow rate at full power is 90 x 6 = 540 cubic ft./min. Now where did I pull the magic number 90 from. Briefly, there are studies that have been published of plume velocities as a function of surface temperature, with induction and with gas. The gas cooking velocity (because the gas combustion products are entrained in the plume) causes more than a meter per second of plume rising velocity. The velocity with induction is typically less than a m/s. At the pan, the hood has NO effect on the velocity, and this essentially holds until the plume is close to the hood aperture. Another way to put it is that the hood captures the plume due to the plume's upward momentum (mass times velocity), which will not change until accelerated or decelerated by some force. When the plume reaches the baffles, it can intercept a gap and pass into the baffle space, or it can hit a metal part and potentially reflect. To keep the reflection in check, the air flow velocity of the hood has to be enough to change the reflection momentum to near zero and let the plume part be pulled into the baffles. When the air velocity is 90 ft/min average across the baffle space, it is about twice that at the baffle gaps, and this velocity is equal to that of the plume velocity. Also, I have observed this level working for the plume over my induction wok, and Greenheck suggests 85 ft/min for similar cooking (Figure 4, page 9 of the previous reference). So think of 90 ft/min as a suggestion that I don't think will prove to be too low. Too low of a hood velocity (CFM/sq. ft.), hence too low of a hood flow rate (below). Enough velocity (below) Blower specification: Yes, the factor of 1.5 is used to make up for the fact that blowers are specified by themselves (usually) hanging in free air, and what you have is a restrictive system that has to deal with baffle restriction, duct, and make-up air pressure losses. The relationship is given by the so-called "fan curve." For example, the Broan blower fan curve immediately below is just about done at well under an inch of water column pressure. Your requirements, depending particularly on baffles and MUA, may require a more "powerful" (higher nominal CFM) blower, as in the second figure. If the only loss were baffles, then the first figure would be barely good enough, because the baffles might have a pressure loss of about one or two tenths of an inch, w.c., at 90 CFM/sq. ft., depending on their aerodynamics. Throw in ducting and pressure losses in the MUA system (a whole giant topic of its own), and the tenths of inches build up leading variously to a need for one of the higher nominal flow rate models.Ekes out 540 CFM at a very low pressure drop (above) A blower with the 1.5 factor achieved (above). Keep in mind 1.5 is only a guess. A blower that would make up for many installation crimes (above), but which drives an unnecessarily more expensive MUA system to keep house pressure up. kas