Rule No. 1: Commercial ventilation is motivated by electrical cost to be the most efficient design. The more a particular hood concept deviates from commercial design the less efficient, and/or less effective the hood will be. This means that baffled hoods mounted over the cooking area and large enough for the height of their entrance aperture to capture rising expanding effluent plumes are best. Commercial ceiling collection schemes involve an entirely perforated ceiling with a plenum above that is kept clean by intense ultraviolet light. You might be able to do this by putting in a false ceiling at 8 feet. However, I don't know how all the ozone that is produced is dealt with in practice. I can guess that kitchen drudges have to clean the ceiling often. Rule No. 2: Everywhere the rising effluent plume reaches needs to have an upward air velocity commensurate with the plume velocity to achieve capture and containment. The slots can only have a small effective range of capture. Rule No. 3: Noise is proportional to air velocity when it is constrained, and using perimeter slots with sufficient air flow (at least 90 cfm per square foot of area of all the possible plumes at the ceiling) should be a real screamer. Most likely, this air flow is not reached with slots, because the pressure loss would be so high that an axial high pressure blower would be needed, and these (typically used for aerospace electronics applications) are only quiet in comparison to jet engines. Rule No. 4: Downdraft capture and containment can only be effective if the air velocity from the downdraft -- at the distance to the furthest edge of any effluent plume -- is sufficient to redirect the effluent to the downdraft screen. Generally, downdraft systems are neither high enough or great enough flow rate to achieve this when hot griddle cooking can achieve an upward plume velocity of 3 ft/s or so, and the air velocity from any aperture including a downdraft aperture drops off very rapidly with distance. You would have to only griddle close to the screen. Overarching Rule No. 5: You get your choice of only two of: Economy, Performance, and Aesthetics. If you want an island or peninsula cooktop with adequate ventilation, you will have to use a sufficiently large island hood, and accept it being a point of (possibly commanding) visual interest. This often means that some expense beyond that needed for functionality will be required to achieve an acceptable appearance. Sight lines should be considered to establish height, from which one can derive necessary aperture size. Note that commercial hood apertures are typically mounted at 7 feet above the floor, but the hoods have significant cooking zone overlap to capture the ever-widening with rise distance cooking plumes. Drafts should be considered as they can move the plumes in some direction causing loss of capture. Rule No. 6: The only air and effluent flow rate that you can move from a hood to the outside is an air flow rate that the internal pressure drop in the kitchen allows to flow into the kitchen. Normally, this is restricted by walls and windows to house leakage. House leakage is inadequate for high performance cooktop ventilation. Further, depressurizing the house can be hazardous if there are combustion appliances in use. To achieve even 2/3 of the rated flow rate of the blower used with a large hood, a make-up air system will be required. See numerous topics here and in other Internet sources for more information. kas

Tyler, so how is it going with the cooktop/hood? We are planning a remodel and considering a similar situation. We are in Florida, so I’d like to avoid MUA if possible as it is painfully humid and hot AF here 360 days of the year and one of my main goals of this remodel is to keep the hot air out. We have an older 1959 home, 94” ceilings. Our kitchen designer wants to put a 36” wolf gas range-style cooktop in front of a 104” window with a 6” backsplash/ledge using a wolf or zephyr 48” ceiling mounted hood at 600 or 700 CFM. So if the cooktop lands at 36”, that puts the vent 4’8”away from the countertop on the ceiling. I’m looking for functionality of suckage (sorry, I never made it past geometry into trig, so “suckage” is as good as it gets for me—lol) and if I have to use a different island hood that hangs 36” above the cooktop, so be it. I’m curious how it’s going for you, especially cleaning the window after cooking. Is it a daily chore or weekly? (I don’t see the window as a cleaning issue, when I cook, most of the splatter winds up on me or flies sideways, but rarely backward—but I’ve been wrong before, and I’ll be wrong again). I just don’t want to make the hood mistake. Any and all input is appreciated ;)

A 30-inch cooktop should have a 36-inch wide hood on a wall, and at a minimum also on an island or peninsula. The front-to-back depth (of the intake opening) needs to be at least 26 inches for island or peninsula use, centered on the cooktop burner/hob arrangement. Example: Wolf Pro Island hoods. Mine is shown below; it is very wide because I have a 36-inch induction cooktop next to a Cooktek induction wok hob. And with respect to pop-ups and down-drafts, consider what is happening in the hood above. I have a 1500 CFM (rated at zero static pressure) blower pulling 1000 CFM (measured) into the hood. The air speed is 100 ft/min or 1.7 ft/s at the aperture, less as one moves the probe downward. A gas cooking plume containing hot oil or grease can reach 4 ft/s. It is the plume that does the work of moving effluent to the hood. The hood only does its work once the plume gets to it. Consider now this huge hood on its side behind the cooktop. Even it would have difficulty fully capturing rear burner hot oil cooking which it has to divert to horizontal flow, and even less success at capturing front burner cooking. Now imagine the likely relative performance possible from slot and perforation apertures of the pop-up vents. They have too low an air flow velocity at a multiple of their narrow slot dimension to divert fast plumes. These devices are not used commercially for a good reason: They can only capture low velocity plumes passing very close to them. Be cautious of any vent design published in kitchen design media; it may have good aesthetic value but poor ventilation performance.

Those old mercury vapor lights are huge, heavy and operate HOT unless re-lamped. The size would distract one's eyes to them and become a focal point, distracting from the rest of the kitchen. They are just tooo big and gaudy, IMO Instead, I would go with a "UFO" LED fixture: https://www.ledlightingsupply.com/commercial-lighting/led-low-bay-lighting/wattage-changing-color-changing-ufo-led-low-bay These are the current replacements in gyms, etc. for the mercury vapor fixtures you have. Size-wise, they would be minimalist in a kitchen and, I think, complement rather than dominate the surroundings. They usually come painted white or black, but they could easily be repainted. Many vendors sell them. The model above has selectable wattage/lumens, but even at the low lumen setting (8,400!) I would connect these to a 0-10v wall dimmer and you would have totally adjustable light output, from low-level romantic up to dazzling brightness. https://www.amazon.com/Leviton-IP710-LFZ-Illumatech-Dimmer-Supplies/dp/B00BUZ6A4E I bought this dimmer new on eBay for ~$25. My experience: I removed 24 mercury vapor fixtures from our church gymnasium and replaced them with 100 watt, 15,000 lumen UFO LED fixtures, and wired all 24 new fixtures to a single0-10 volt dimmer. Really works nice!