By the way, the path for the ductwork that I indicate is the only one available.

HI -- First of all Ricardo .... are you going to use it , do you need it or do you think you should just have one for looks . The reason I say this is because I have one and really only use the light on it . Because of the way I cook now ( induction cooktop ) I don't find I really need or use the fan . Maybe you should get someone to help you install this . A professional installer . At least spend the money on that to make sure it is installed properly .

@lefty47 Yeah, I'm definitely going to use it, maybe not for deep frying, but for all the rest yes. I don't like the smell of food in a house, and with the open concept, this will be an issue. Will I use it often, no, I'm single and I eat a lot of take-away... some of the things that I cook are risottos, soups, Thai and a lot of sautee...

Can you do 8"? Looks like your run to outside will be quite far and small diameter venting will increase your resistance to flow tremendously. You can easily construct your own venting with parts from the furnace section of your local hardware store. From the hood, you can use sheet metal and an 8" collar to cap the hood and join it to the rest of the venting. I think it's much better to just go circular venting all the way.

@mishmosh Yeah, I think I could, I would like that the ductwork, and whatever conceals it, remains recessed with respect to the hood's duct cover. That is about 7 inches...

The OP may not have looked very deeply into this forum, but there is a wealth of hood information available. Here are some highlights:

Cooking odor rises with cooking water vapor, cooking grease vapor, and cooking smoke. The velocity of this rising and expanding effluent plume from each hot surface varies with the temperature of the plume and whether hot gas combustion products are also present. Velocities in the 0.6 to 1.2 m/s may be observed.

To capture the odor and everything else requires a hood large enough to encompass the plumes at the height selected for the hood. The hood has to overlap the pan bases, and this generally means the hood has to overlap the cooktop. If it does, then the capture part of a hood's essential function of capture and containment can be met.

For containment, the effluent has to be moved from the kitchen side of the hood filter to the duct side of the hood filter without having any "reflect" out of the hood. A suggested air velocity for this purpose is 90 ft/min (roughly 0.5 m/s). This is equivalent to 90 CFM per square foot of hood aperture.

Given this flow rate, the duct should be sized for around 1000 ft/min velocity, but this can be as low as 500 and as high as 2000. Cold ducting can influence the choice of velocity to minimize grease collection by impingement. Planning ahead for a different hood can also influence the selection.

I don't have a particular opinion about what is most aesthetic, but would lean toward rectangular covers that hide the ducting. An external blower will be modestly quieter than an internal blower. If an external blower is used, a silencer may be used between the blower and hood to further reduce noise. I don't know if such silencers (e.g., Fantech) are widely available outside the USA.

Noise levels depend on the source, but from typically loudest to less loud, the order is:

• blower blade tip turbulence
• baffle or mesh turbulence
• duct turbulence
• motor vibration

kas

@kaseki

Thanks for that very thorough explanation!

Indeed, there are many topics about range hoods, this is why I decided to ask here and nowhere else.

My concern is not so much regarding the aspiration capacity, my concerns in order are 1) Aesthetics and 2) Noise. I know my range hood is limited to 380 m3/hr (220 cfm), so 6" is already a lot! But I don't want to sacrifice on the installation given the plans to put in the future something better.

I agree that a wider hood will help to trap the vapors and odors better, but again, I don't cook on a daily basis, and when I do, I don't do deep frying or slow cooking stews.

Thanks for pointing out something important, my stove is gas, not electric, so I need to account for the combustion fumes too.

Thanks!

You mention this is in an apartment do you have permission to actually vent to the outside where there has to be a hole to allow that, in most cases that is not allowed in a condo or apartment building.

@Patricia Colwell Consulting

Yes, it is allowed, the storage area is actually a "loggia" intended as a laundry room, where several exhausts are allowed (tumble dryer, gas boiler, range hood), and others are of course forbidden (coal boiler, chimney, grill exhaust, etc). The flat came with a range hood with integrated active charcoal filters. These units are mostly equipped very poorly, and the selection of appliances is made based upon time of completion and cost (in that order).

Charcoal filters are useless unless cleand almost every day so you are lucky to be able to install a proper hood.

Are you a licensed and insured contractor? Have you pulled the permits to do this extensive renovation? In a multi family building, you are required to use licensed and insured Contractor for your renovations. One your building approves. You may have just voided your agreement with your building and your insurance company.

@Sophie Wheeler My sister is an architect and I'm an engineer, we know the local codes relatively well and we tried to stay within the limits, so that permits would not be necessary. But I will double check, especially with my insurance company, you made me a bit afraid of any small print in there. Thanks for pointing that out :-)

@Sophie Wheeler, Ricardo lives in Chile. So, I assume all of the rules, regulations and laws are subtly different from what happens in the US. Hard to make any suggestions about those. Of course, the technical and product advice is mostly unaffected.

@Patricia Colwell Consulting, you are generally right about how useless charcoal filters are. The consensus in this forum appears to be that the only worthwhile recirculation system is Vent-A-Hood's ARS. I don't have any first-hand experience with it. But several people have said that as long as it is sized properly and maintained according to Vent-A-Hood's recommendations, it works surprisingly well.

@Ricardo Parra, 220cfm sounds low. This is doubly true, as your true flow rate is likely even less than that. Any bend in the duct severely reduces flowrate. I am afraid, with an open floor plan, all your meticulous planning is going to mostly result in an elaborate mechanism to make noise -- and not in an effective tool to remove cooking smells. Open floor plans are tricky that way. Is there any way you can increase the duct diameter to 8" and increase the CFM rating of the hood?

@M

Yes, when I bought it the flow in the box said 770 m3/hr, but on the manual, on the small print, it stated 380 m3/hr according to EU Nº 65/2014 & 66/2104, that's roughly 220 cfm, and I agree, that's pretty low, but that must probably the true flow. The fan is only 115 W.

The hood came with a reducer from 150 to 120 mm (5 to 6 inches roughly), and they recommend to use the lower size, probably based on the flow rate, but I'm still gonna go with the biggest diameter I can in case I change it in the future. I could go for 8 inches, and connecting with 6" to the hood from the bottom without using an elbow.

You are right about codes too, there are some areas where it can be very strict and outdated, especially in the use of new plastic choices (self-extinguishable polymers for example, I lived for almost 10 years in Germany, and I did this twice using white plastic ductwork). The code, in general, is strict in regard to seismic activity and environmental. As for using licensed contractors, the system stopped being regulated long time ago, and the rule is, if you want it excellent, either pay a lot to a company (not contractor) or do it yourself.

i would rather use it for deep frying....it makes sense