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How do vent your cooktop and does it work well?

Posted by khj133 (My Page) on
Sat, Dec 4, 10 at 0:18

Do you use an overhead hood, over the range microwave, or downdraft ventilation?

What hood are you using?

What is the style - standard, chimney, canopy pro style or custom wood with insert?

Wall mount, under cabinet or Island mount?

What type of blower - internal, remote or inline?

How many cfms?

Ducted or Non-ducted?

How do the ducts go to the outside? Length, turns,size, thru attic, down into basement?

Do you find it too loud?

Do you have make-up air?

If a renovation, then how hard was it to install ducts and how much did it cost?

If a new build then did builder charge you more to duct one way or another?

Most importantly, is it effective and work for your needs?


I have been struggling with my kitchen layout because the builder tells me there is only one wall to vent a hood efficiently with 2 turns and a total 10 feet run to the outside wall with an adapter or attachment for a plumbing pipe in the way. Any other wall requires me to have a duct go down into the basement with 2 turns and 40 foot run total. When I called the vent-a-hood, their technician told me that going down to basement would be too long a run and effectively make my expensive vent hood useless.

Somebody just told me that ducts can go between studs on the wall and then thru attic and out thru the roof. My builder and HVAC person did not tell me of that route. I have a bathroom above the kitchen and so the duct could go between the studs of the wall of the bathroom and into attic. I don't know if there are truss issues that make this difficult. But is this a better way to vent the hood? I have 10 feet ceiling in kitchen, 9 feet on second floor and then the attic. Is that too long?

I currently have an over the range microwave which does not do an effective job for my type of cooking. Hence im my new build it is important to have a powerful effective hood. I was thinking of getting the 48" Kobe 1000 cfm chimney style hood as that would require an 8 inch duct and builder says I can't go with a bigger duct size.

I am learning as I go. It would be helpful to read your experience.


Follow-Up Postings:

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RE: How do vent your cooktop and does it work well?

  • Do you use an overhead hood, over the range microwave, or downdraft ventilation?

    Ans: Overhead hood (42" wide x 24" deep over a 36" cooktop)

  • What hood are you using?

    Ans: Vent-A-Hood's SEPH18 Euroline Pro with Emerald Lip

  • What is the style - standard, chimney, canopy pro style or custom wood with insert?

    Ans: Chimney

  • Wall mount, under cabinet or Island mount?

    Ans: Wall mount

  • What type of blower - internal, remote or inline?

    Ans: Internal blower

  • How many cfms?

    Ans: 600 (although, Vent-A-Hood claims it has the same effectiveness as 950cfms b/c of it's "Magic Lung" system)

  • Ducted or Non-ducted?

    Ans: Ducted externally

  • How do the ducts go to the outside? Length, turns,size, thru attic, down into basement?

    Ans: The duct work goes up an interior wall to the kitchen ceiling.
    .......It then "turns the corner".
    .......Next, it is converted from an 8" round duct to a 6" x 8-1/2" rectangular duct.
    .......Then, it crosses the kitchen (10'6")
    .......It then makes another turn to fit under the 2-foot 2nd floor overhang (I can't remember what it's called right now)
    .......And then another turn to vent out the back exterior wall

  • Do you find it too loud?

    Ans: No. Even on high I can still carry on a conversation...albeit we do have to speak a little louder to the person working at the cooktop, but not that much louder (i.e., no yelling). The person cooking can also watch TV while working. Lastly, you can hear the Christmas Music (or whatever music) from the ceiling speakers while cooking.

  • Do you have make-up air?

    Ans: No

  • If a renovation, then how hard was it to install ducts and how much did it cost?

    Ans: Keep in mind we had the work done in early 2008, during the remodeling boom.

    First, we had to move the shower drain of the Master Bath b/c it was in the way. It cost us approx $900 to do it, but we could have done it for $550...we took the middle bid for the work.

    As to the removal of old 4" duct & installation of the new duct in a new location:
    ...Removal of existing range hood duct: $233.33
    ...New duct work for vent blower-8" pipe: $300.00
    ...F&I exterior vent, does not include new siding: $260.00
    ...Installation of vent hood: $300.00
    ...Connect duct to vent: $245
    ...Duct cover: $269.10
    This is probably more than you asked, but I wanted to give you the full cost of everything other than the vent hood itself.

  • If a new build then did builder charge you more to duct one way or another?

    Ans: N/A

  • Most importantly, is it effective and work for your needs?

    Ans: Yes, so far it has indeed been effect for how I cook...boil water quite a bit for various things, occasionally brown meat (chili, tacos, sloppy joes, etc.), grilled sandwiches, scrambled eggs, etc. I don't stir-fry or fry foods and I have no grill (just a "vanilla" electric cooktop).

    I will say, though, that I'm glad I got the 42"Wx24"D hood b/c it catches the steam, smoke, etc. that starts spreading...the spreading is most noticeable when watching the steam from a pot of boiling water.

    I've also noticed that I no longer smell the hours old cooking odors throughout the house...I used to have to keep our bedroom door closed b/c otherwise I would go to bed smelling what I cooked that evening...and our bedroom is on the second floor at the far end of the house from the stairs. Note that I did have a range hood in our old kitchen, but it was a builder-grade 30" externally-vented hood w/a 4" duct over a 30" range, but, it didn't work very well (I think it was a Nautilus). (Yes, it was surrounded by upper cabinets but they didn't help corral the smoke/steam/grease/etc.)


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RE: How do vent your cooktop and does it work well?

I have a big, overpowered hood. It's 48" wide (a bit bigger than the cooking area), and vents right out the wall behind it (internal blower) so there's no loss of suckage. It's 1200 cfm, but has a continuous control knob (like a volume knob), rather than stepped settings, and I rarely crank it up all the way. I don't know the details, but Trailrunner, whom I trust entirely on the subject, says that more powerful on a lower setting is more efficient.

It's a Modern-Aire. The style is a little old world, a little contemporary. It fits under cabinetry, but curves out to a rectangular lip. Mine is brushed brass with polished brass vertical bands, lip and pot rail. This is a style that a number of us chose at about the same time. Modern-Aire are local to me, and made my previous hood, but right after I ordered my new one they gained popularity on GW, and there were several of the same design in kitchens that were finished before mine. The fun thing is that they're all different! One is stainless, one is red, one has copper bands, I think.

Because it's so powerful, it's not whisper quiet, but it's not annoyingly loud either. The Modern-Aire website has a PDF file with graphs of the sound/air movement. No make-up air. Everyone thought there was enough air volume in my house, and it's not tightly sealed. Plus, a moderate climate. When I crank it up high I can open a little window in the kitchen.

Even just cutting a hold in the wall took some care. I have all my services out that wall, so it had to fit where the inverter wasn't, and all of that. Luckily, there was just about room right where I wanted it. My HVAC guy had to come and bend the A/C pipe around it, but it wasn't a big deal. It's stupid that there was no ducting put into this house, but there are advantages to being able to vent directly outside.

Most importantly, is it effective and work for your needs?

Um... YES.

I can't advise you about the ducting, but venting up definitely works best. Physics and all of that. You can get more powerful blowers to deal with the difficulties with the ducts. Actually, I think there are some issues with venting between the joists because of the shape of the cross section or something, but it might be something that can be overcome. Sometimes an additional blower helps, or just a slightly stronger one.

Best of luck!


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RE: How do vent your cooktop and does it work well?

Thank you Buehl and Pllog for your detailed responses. I know I asked a lot of questions but I thought it would be helpful for others like me who don't know anything about hoods and ductwork to read many experiences to make the best decision.I tried to search for more threads regarding venting but was not very successful.

Would love to get more responses even if they are short. It would be a great way to compare hoods, ductwork, etc.


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RE: How do vent your cooktop and does it work well?

I have a 600cfm VentaHood wall mount chimney style hood with internal fan. It's ducted straight up (mostly, with a few mild doglegs) through the attic and roof. It has 3 power settings, and like buehl, I don't find it excessively noisy, even on High. However, mine is only 19" deep. While the advice here and on the appliance forum was to get a deeper 24+" hood, my dealer insisted that was not available. I wish I had made a bigger fuss about it, since it ultimately became clear he was pretty ignorant about most stuff he was selling (high end, high price, high reputation, low competence). Anyway, I've learned to work around this situation, and do the greasiest smokiest cooking on the back burners.

I had to have heated make-up air installed, because that is code here for any fan of this capacity. It was HUGELY expensive - more than the hood, range, and DW combined. But necessary, as I have gas furnace and water heater, and windows freeze shut here for several weeks/months at a time. 600cfm can evacuate my entire house in 36 minutes.


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RE: How do vent your cooktop and does it work well?

Here I thought winters here in Wisconsin are bad! Cooknews, may I ask where you live that your windows freeze shut several weeks/months at a time?

Do you have a 2nd floor above your kitchen? Are the doglegs in the attic to get around trusses? Does cold air come in thru the hood. Our hvac person had once claimed that people don't like to vent thru the roof as there is greater chance of cold air coming in. Do you think that is true?

Thank you Cooknews for your response. It helps to get another perspective.


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RE: How do vent your cooktop and does it work well?

I've had an OTR for years with 2 different microwaves. The venting function is better than nothing, but not great. It's not unusual for our smoke alarm to go off when we use the high heat burner.


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RE: How do vent your cooktop and does it work well?

Do you use an overhead hood, over the range microwave, or downdraft ventilation?
overhead hood

What hood are you using?
Ikea Luftiq

What is the style - standard, chimney, canopy pro style or custom wood with insert?
Chimney

Wall mount, under cabinet or Island mount?
Wall

What type of blower - internal, remote or inline?
Internal

How many cfms?
400

Ducted or Non-ducted?
Ducted

How do the ducts go to the outside? Length, turns,size, thru attic, down into basement?
Goes outside, through the attic, 2 turns, 6" duct work..

Do you find it too loud?
eh, not really. I was expecting worse for a $400 hood

Do you have make-up air?
I don't know what that is

If a renovation, then how hard was it to install ducts and how much did it cost?
Not hard because the part of our attic we can stand-up in - DIY so $50 for ducting/tape, $35 for the roof vent and I don't know how much we paid the roofing company to flashs b/c we had to get all new flashing for some old vent pipes n such. We have a 12/2 pitched roof so we didn't feel comfortable getting up there..

Most importantly, is it effective and work for your needs

Yes! our first meal was a beef tenderloin - we seared it and it worked great. We have a smoke detector within 3 feet and it didn't alarm. I was expecting to have to upgrade in a few years but I'm really pleased.


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RE: How do vent your cooktop and does it work well?

I live on the Canadian prairies, where daytime temps have been below freezing for at least the past 3 weeks.

There is no 2nd floor above my kitchen. I'm not exactly sure why the doglegs in my ducting, perhaps truss avoidance, but I think the HVAC guy wanted to position the exterior vent at a particular place on the roof relative to the peak for optimum performance. There is a cap on the vent that prevents outside air leaking in. It works well, although I can hear it jiggling some on windy days.


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RE: How do vent your cooktop and does it work well?

I have a 1600 cfm prestige fan with external blower. I think it's 46" but centered in a wood hood 54" x 27" over a 48" Bluestar range. It has 2 bends and travels about 6' to an outside wall. (It could have went to the roof but that part of the house has a flat roof and I was worried if I try to start the vent and we just had 2' of snow) 10" ductwork so that the pantry ceiling was dropped a few inches (the kitchen was taken down to the studs so that was easy to do). It has the same type of control as plllog - continuous control knob. It's quieter than my old recirculating fan that I wonder if it's really sucking 1600 cfm. No make up air but I have an old 1825 house with lots of windows and doors. Love my vent!


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RE: How do vent your cooktop and does it work well?

I have a 600 CFM Best by Broan hood with the optional baffles.
Hood is 36 wide by 24 deep.

I have 6 burner Thermador All Gas range. Burners are deeper by just a bit than the hood. Range is against the wall, so a good capture area.

Hood is vented vertically; roof right over the kitchen.

6 inch round duct.

Like the hood very much. We do a lot of stir frying and such, and this hood is excellent. Never have the smoke detector go off.

In fact, when we first remodeled, I kept burning stuff in the oven, because there was no smell in the house of what I was cooking.

No makeup air system. We have a 1931 house with stone foundation, so get lots of infiltration. I do crack a window if stir frying, just to draw in a bit more fresh air to the kitchen.

Remodel was about 10 years ago, so don't remember costs.


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RE: How do vent your cooktop and does it work well?

Do you use an overhead hood, over the range microwave, or downdraft ventilation?
Overhead hood

What hood are you using?
Wolf Pro Island Hood around 60 inches long. Captures effluent from 36-inch induction hob cooktop and nearby wok induction hob.

What is the style - standard, chimney, canopy pro style or custom wood with insert?
See Wolf literature

Wall mount, under cabinet or Island mount?
Island mount over peninsula

What type of blower - internal, remote or inline?
External Wolf supplied, Broan/Nutone manufactured. Works with variable control on hood.

How many cfms?
1500 nominal at zero static pressure, but probably around a 1000 on max setting at -0.1 inches of house pressure with baffles in place, ducts, and silencer. House calibration has not yet begun.

Ducted or Non-ducted?
ducted

How do the ducts go to the outside? Length, turns,size, thru attic, down into basement?
Up a few feet to attic, ~80 degree bend to a Fantech silencer, then some more duct and another ~80 degrees to the roof. Length hasn't been measured, but might be around 20 feet.

Do you find it too loud?
No

Do you have make-up air?
A work in progress. MUA will have to dynamically compensate for this hood at any setting, a variable 1000 cfm nominal (probably up to 600 actual) vented filtered diffuser pair over the wall ovens, three bathroom fans, various states of window openings, fireplace, and furnace.

If a renovation, then how hard was it to install ducts and how much did it cost?
Too difficult to separate out from kitchen ceiling reconstruction, re-insulating the attic, etc. I may not want to know.

If a new build then did builder charge you more to duct one way or another? N/A

Most importantly, is it effective and work for your needs?
Yes.


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RE: How do vent your cooktop and does it work well?

Thank you for your feedback. I see variety of hoods that do work effectively.

Igarvin and Kaseki, do you have a 2nd foor above kitchen or is it straight to attic and roof?

Is there anyone with 2nd floor above kitchen and have yet been able to have the ducts go up to the roof?


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RE: How do vent your cooktop and does it work well?

An attic is above my kitchen. If there were a second floor, a chase would be needed to contain the 10-inch round ducting, and another chase for the 8-inch round ducting for the oven vent. The chase would have to fit the larger diameter silencers unless there were an attic to put them in. Lining such chases with firecode sheetrock would be advisable. Chase positioning would constrain the kitchen layout, I imagine.

Alternatively, and more practically if new construction, ducting can be rectangular and lie within the studs. Six-inch studs might be a good idea in this case, On an outside wall one would want some insulation besides the duct. A larger dual-ducted hood could be ducted through two stud cavities.

kas


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RE: How do vent your cooktop and does it work well?

I have 36" 600cfm Thermador connected to 1 elbow discharging through an 8"w x 8' long straight run out the side of the house. We only ever use the lower settings and do not have any odor issues in our very open floorplan. The higher settings are somewhat loud.

The HVAC guy will be able to figure out if you need makeup air based on all your bathroom fans and such. I failed inspection due to the 600cfm Thermador so had to replace it for reinspection otherwise it would have been a few thousand dollars for tempered makeup air.

I didn't pay extra to the HVAC contractor for the 8" duct.


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RE: How do vent your cooktop and does it work well?

Thank you Kas for the info. If one is not able to put in 6" studs then would 4" be ok? Would it be too long a run if I were to get the duct within studs to attic and then out the roof since I have a bathroom on top of kitchen? In this case would external blower with silencer be better than an internal blower?


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