Can't really give any info without knowing what is this going to be over? Gas or electric? Also, which blower where you choosing? Just how did consummer reports rate this? In comparison to what? This design is noisy and not efficient for extraxtion but these are relative terms. Also, my experience is that they are 1/16 of an inch less wide than the specs. I think 1/8 would be real tight.

All day, everyday customers ask me what are the best appliances because their expensive two year old appliance is broke. I always tell them the cheapest ones. If a frig is full of electronics it will break and cost 2-4 hundred to repair it. A basic simple no fancy electronic frig will last. Whirlpool or Frigidaire. The fancier the range the better for me. Keep it simple. All ovens heat at 350 degrees. It seems today everyone is a chef, must be all those cooking shows. They buy $2000.00 ranges and pay me $400.00 to fix them. I love it. People pay big bucks on a dishwasher with all those buttons but only use the normal cycle. I don't get it. A mid line whirlpool is a good dishwasher. All dishwashers work about the same. Water comes in, sprays around, and drains. Its not magic. If you like the Bosch, Samsung, Miele, asko etc. make sure there are people in town that repair them. I'm like the only LG servicer in my area which means I can charge more to repair them. No competition, business 101. There are only a couple of people in my area that will repair Samsung refrigerators, bosch, asko, etc. And they are not cheap. Everyone repairs Whirlpool and Frigidaire. I live in an area with over 500,000 people so its not like we're in a small town out in the boonies. Talk to an independent local servicer that doesn't sell appliances and he can advise you on the appliances that he has the least problems with. You won't find too many appliance tech's that own GE. Their parts are the most expensive in the industry. Whirlpool, Frigidaire and even LG parts are reasonable. Fischer Paykel. There again one maybe two companies repair them. The only place I can find parts for them is from Fischer paykel and they're in New Zealand. Takes about 3 weeks to get parts. I just picked up a customer with apartments full of Viking. Viking controls their part distribution so only one part supplier on the east coast carries the parts. No competition means expensive parts which equals expensive repairs. Its a great time to be an appliance repairman. I was never this busy in the 90's with the simple basic appliances. All those new fancy electronic appliances keep me very busy.

Wouldn't be a fast process unless you were just planning on harvesting mosses from outside. (And if you should go that route, please restrict the depredations to the yard of your own or a friend/relative. (Many of whom would likely be more than happy to allow you to do so.) Lichen generally make very poor terr candidates -- they need very good air circulation. do a forum and Google search for growing mosses. (Believe there is a moss forum to so definitely cross post there.). Let us know how it goes!

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.