General fitness, health and nutrition · Public discussion

Range hood performance

Started by David Hare-Scot · · Last activity · 14 posts · 702 views

This thread is locked and is currently read-only.

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

Thread details

What we know about this thread

Original section
General fitness, health and nutrition
Published
5 July 2004
Last activity
5 July 2004
Original author
David Hare-Scot
Posts
14
Discussion status
Public discussion
Total views
702
Views / 30 days
0

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–14 of 14
Posts remain in their original chronological order.

Text size
  1. I am in the process of setting up a new kitchen and I am
    getting frustrated about range hoods. I want a range hood
    that really works (ie extracts smoke, smells and steam
    efficiently) but I cannot afford to pay the earth.

    Appliance shops deluge you with sales bull and explain
    nothing. You can get a hood from $200 to $2000. Some of the
    larger and fancier ones have more stainless steel and bells
    and whistles but some look just the same and have a price
    tag twice (or half) as much. When asked to explain the
    difference you get "the more expensive one is better" if you
    ask better in what way exactly you get told about features
    but not performance. I can make my own jugements about ease
    of cleaning and if I need frisbees on the thingajig or gold
    plated whatsernames.

    I have looked at professional cooking gear web sites but so
    far it seems that you have to have qualifications in air
    conditioning engineering to follow their specs and most of
    the products assume a restaurant sized operation.

    One web site recommends that the hood be able to extract
    between 6 and 12 times the volume of the room per hour. That
    is you turn over the air every 5 to 10 minutes, this seems
    reasonable to me.

    Does anybody have any views on that? Under what
    circumstances would the upper or lower rate be appropriate?

    How else might one assess the required rate?

    David

  2. Quoted message said:

    "David Hare-Scott"

    I am in the process of setting up a new kitchen and I am
    getting frustrated about range hoods. I want a range hood
    that really works (ie extracts smoke, smells and steam
    efficiently) but I cannot afford to pay the earth.

    The only truly efficient range hoods vent to the outdoors.
    Essentially only you can assess your budget... but efficient
    exhaust systems can cost as little as US$200... and after
    that the sky's the limit. Without knowing the exact
    configuration of your kitchen no one can offer more than
    wild speculation as to which style to obtain and
    installation costs. Good luck.

    ---= BOYCOTT FRANCE (belgium) GERMANY--SPAIN =--- ---= Move
    UNITED NATIONS To Paris =---
    *********
    "Life would be devoid of all meaning were it without
    tribulation." Sheldon ````````````

  3. "David Hare-Scott" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    I am in the process of setting up a new kitchen and I
    am getting


    frustrated

    Quoted message said:

    about range hoods. I want a range hood that really works
    (ie extracts smoke, smells and steam efficiently) but I
    cannot afford to pay the earth.

    Appliance shops deluge you with sales bull and explain
    nothing. You can


    get

    Quoted message said:

    a hood from $200 to $2000. Some of the larger and fancier
    ones have more stainless steel and bells and whistles but
    some look just the same and


    have

    Quoted message said:

    a price tag twice (or half) as much. When asked to explain
    the difference you get "the more expensive one is better"
    if you ask better in what way exactly you get told about
    features but not performance. I can make my


    own

    Quoted message said:

    jugements about ease of cleaning and if I need frisbees on
    the thingajig


    or

    Quoted message said:

    gold plated whatsernames.

    I have looked at professional cooking gear web sites but
    so far it seems that you have to have qualifications in
    air conditioning engineering to follow their specs and
    most of the products assume a restaurant sized operation.

    One web site recommends that the hood be able to extract
    between 6 and 12 times the volume of the room per hour.
    That is you turn over the air


    every

    Quoted message said:

    5 to 10 minutes, this seems reasonable to me.

    Does anybody have any views on that? Under what
    circumstances would the upper or lower rate be
    appropriate?

    How else might one assess the required rate?

    You might ask over at rec.food.equipment. This is a much
    discussed topic. Most people agree that the hood should be
    larger than the cooking surface. The capacity in CFMs is
    dependant on the BTUs and the type of cooking. If you are
    going to grill, then you should error on the larger end.
    For typical cooking on a typical residential range you
    probably need between 600 and 1200 CFM. If your house is
    new and very tight, you can create dangerous downdrafts in
    chimneys (fireplace, water heater, furnace,) if the hood is
    too large and you don't have a source of make-up air. One
    rule of thumb that I have seen is that you need 10 CFM per
    1000 BTU of output from the stove. On thing to keep in mind
    is that the ratings for hood drop as you increase the
    length of duct and for each change of direction. There is
    also a drop associated with the resistance of the damper
    that terminates the duct.

  4. David Hare-Scott said:

    I am in the process of setting up a new kitchen and I am
    getting frustrated about range hoods. I want a range hood
    that really works (ie extracts smoke, smells and steam
    efficiently) but I cannot afford to pay the earth.

    Do the prospective hoods vent to the outside or to the
    inside? Some states require it, and in those that don't it's
    almost never an option in a house (and never an apartment).

    Hoods that vent to the inside are useless unless you do a
    lot of [deep] frying.

    -sw

  5. David Hare-Scott said:

    if you ask better in what way exactly you get told about
    features but not performance.

    Ask them how many CFM (cubic feet per minute) of air the
    hood moves. Calculate the cubic feet in the area you're
    venting and take it from there.

    To further confuse you, have you considered an "exterior"
    mounted fan?

    More food for thought fantech.netrhl.htm

    Practice safe eating - always use condiments

  6. David Hare-Scott said:

    I am in the process of setting up a new kitchen and I am
    getting frustrated about range hoods. I want a range hood
    that really works (ie extracts smoke, smells and steam
    efficiently) but I cannot afford to pay the earth.

    Another thing to think about is noise. The hoods are rated
    in "sones" according to how quiet they are. That's also
    important to me in my tiny house.

    Good luck. I have one picked out but getting someone to
    install it is a problem.

    broan.comproduct detail.asp

    Sue(tm) Lead me not into temptation... I can find it myself!

  7. "Vox Humana" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:


    You might ask over at rec.food.equipment. This is a much
    discussed topic.

    Thanks I will try their archives first.

    Quoted message said:

    Most people agree that the hood should be larger than the
    cooking surface.

    This is hard to arrange since hoods come in the same sort of
    size as cooktops, I suppose if I had a 60cm cooktop I could
    use a 90cm hood but I have a 90cm cooktop.

    Quoted message said:

    The capacity in CFMs is dependant on the BTUs and the type
    of cooking. If you are going to grill, then you should
    error on the larger end.

    Agreed

    For

    Quoted message said:

    typical cooking on a typical residential range you
    probably need between


    600

    Quoted message said:

    and 1200 CFM.

    Using the 12 times room volume per hour rule of thumb I get
    230 CFM, hmmmm

    If your house is new and very tight, you can create
    dangerous

    Quoted message said:

    downdrafts in chimneys (fireplace, water heater, furnace,)
    if the hood is too large and you don't have a source of
    make-up air.

    My house will be very tight so I will keep this in mind.

    One rule of thumb

    Quoted message said:

    that I have seen is that you need 10 CFM per 1000 BTU of
    output from the stove.

    I will have to work on this one.

    On thing to keep in mind is that the ratings for hood
    drop as you

    Quoted message said:

    increase the length of duct and for each change of
    direction. There is


    also

    Quoted message said:

    a drop associated with the resistance of the damper that
    terminates the duct.


    The tube will go straight out the wall behind the
    stove, a total length of about 60cm (2ft) so these
    effects will be minor

    David

  8. "Steve Wertz" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:
    David Hare-Scott said:

    I am in the process of setting up a new kitchen and I am
    getting


    frustrated

    Quoted message said:
    Quoted message said:

    about range hoods. I want a range hood that really works
    (ie extracts smoke, smells and steam efficiently) but I
    cannot afford to pay the


    earth.

    Quoted message said:


    Do the prospective hoods vent to the outside or to the
    inside? Some states require it, and in those that don't
    it's almost never an option in a house (and never an
    apartment).

    Hoods that vent to the inside are useless unless you do a
    lot of [deep] frying.

    -sw

    It vents straight outside, I agree the recirculating type
    are fairly useless.

    David

  9. "sf" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:
    David Hare-Scott said:

    if you ask better in what way exactly you get told
    about features but not performance.

    Ask them how many CFM (cubic feet per minute) of air the
    hood moves. Calculate the cubic feet in the area you're
    venting and take it from there.

    I can do all the required sums and most manufacturers
    specify the volume extracted, the thing that I am having
    trouble with is the basis for calculation of the desired
    rate of extraction.

    Quoted message said:

    To further confuse you, have you considered an "exterior"
    mounted fan?

    Since my duct will be very short, about 60cm (2ft) I cannot
    see that the position of the fan will make much difference
    but please enlighten me if I am wrong.

    Quoted message said:

    More food for thought fantech.netrhl.htm


    This site is interesting, they give a rule of thumb for
    bathrooms of 8 air changes per hour but I cannot find
    anything on kitchens.

    David

  10. "David Hare-Scott" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:


    "Vox Humana" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:


    You might ask over at rec.food.equipment. This is a much
    discussed


    topic.

    Quoted message said:


    Thanks I will try their archives first.

    Quoted message said:

    Most people agree that the hood should be larger than
    the cooking


    surface.

    Quoted message said:


    This is hard to arrange since hoods come in the same sort
    of size as cooktops, I suppose if I had a 60cm cooktop I
    could use a 90cm hood but I have a 90cm cooktop.

    In the US, cooktops and ranges generally come in widths from
    24 to 60 inches in 6 inch increments as do hoods. For a 36
    inch range, you would order a 42 inch hood.

  11. David Hare-Scott said:


    "sf" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:
    David Hare-Scott said:

    if you ask better in what way exactly you get told
    about features but not performance.

    Ask them how many CFM (cubic feet per minute) of air
    the hood moves. Calculate the cubic feet in the area
    you're venting and take it from there.

    I can do all the required sums and most manufacturers
    specify the volume extracted, the thing that I am having
    trouble with is the basis for calculation of the desired
    rate of extraction.

    Basis? Is this one big room? If so, calculate that.

    Quoted message said:
    Quoted message said:

    To further confuse you, have you considered an
    "exterior" mounted fan?

    Since my duct will be very short, about 60cm (2ft) I
    cannot see that the position of the fan will make much
    difference but please enlighten me if I am wrong.


    Noise.

    Quoted message said:


    Quoted message said:

    More food for thought fantech.netrhl.htm


    This site is interesting, they give a rule of thumb for
    bathrooms of 8 air changes per hour but I cannot find
    anything on kitchens.


    You can't extrapolate?

    Practice safe eating - always use condiments

  12. "sf" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:
    Quoted message said:


    I can do all the required sums and most manufacturers
    specify the


    volume

    Quoted message said:
    Quoted message said:

    extracted, the thing that I am having trouble with is
    the basis for calculation of the desired rate of
    extraction.

    Basis? Is this one big room? If so, calculate that.

    We don't seem to be on the same wavelength here. I can
    calculate the volume of the the room, I know what the
    heating capacity of my cooktop and oven are. The question is
    what is the basis of computation of the required extraction
    rate to service that room?

    Quoted message said:
    Quoted message said:
    Quoted message said:


    This site is interesting, they give a rule of thumb for
    bathrooms of 8


    air

    Quoted message said:
    Quoted message said:

    changes per hour but I cannot find anything on
    kitchens.


    You can't extrapolate?

    No I cannot. I don't have a 50 Mj gas stove in the bathroom.
    I don't fry and produces any smoke in the bathroom. Please
    explain how to extrapolate from bathrooms to kitchens.

    David

  13. David Hare-Scott said:


    "sf" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:
    Quoted message said:


    I can do all the required sums and most
    manufacturers specify the


    volume

    Quoted message said:
    Quoted message said:

    extracted, the thing that I am having trouble with
    is the basis for calculation of the desired rate of
    extraction.

    Basis? Is this one big room? If so, calculate that.

    We don't seem to be on the same wavelength here. I can
    calculate the volume of the the room, I know what the
    heating capacity of my cooktop and oven are. The question
    is what is the basis of computation of the required
    extraction rate to service that room?


    You're making it harder than it is. How many cubic feet of
    air do you want moved per minute? Take it from there.

    Quoted message said:


    Quoted message said:
    Quoted message said:

    >
    This site is interesting, they give a rule of thumb
    for bathrooms of 8


    air

    Quoted message said:
    Quoted message said:

    changes per hour but I cannot find anything on
    kitchens.


    You can't extrapolate?

    No I cannot. I don't have a 50 Mj gas stove in the
    bathroom. I don't fry and produces any smoke in the
    bathroom. Please explain how to extrapolate from
    bathrooms to kitchens.


    cfm is your friend. If that's too hard for you, go to a
    restaurant and find out what they use. I'm sure it will meet
    your requirements.

    Practice safe eating - always use condiments

  14. sf said:
    David Hare-Scott said:


    "sf" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    >
    > I can do all the required sums and most
    > manufacturers specify the


    volume

    Quoted message said:

    > extracted, the thing that I am having trouble with
    > is the basis for calculation of the desired rate of
    > extraction.
    >

    Basis? Is this one big room? If so, calculate that.

    We don't seem to be on the same wavelength here. I can
    calculate the volume of the the room, I know what the
    heating capacity of my cooktop and oven are. The
    question is what is the basis of computation of the
    required extraction rate to service that room?


    You're making it harder than it is. How many cubic feet of
    air do you want moved per minute? Take it from there.

    Quoted message said:


    Quoted message said:

    > >
    > This site is interesting, they give a rule of thumb
    > for bathrooms of 8


    air

    Quoted message said:

    > changes per hour but I cannot find anything on
    > kitchens.
    >
    You can't extrapolate?

    No I cannot. I don't have a 50 Mj gas stove in the
    bathroom. I don't fry and produces any smoke in the
    bathroom. Please explain how to extrapolate from
    bathrooms to kitchens.


    cfm is your friend. If that's too hard for you, go to a
    restaurant and find out what they use. I'm sure it will
    meet your requirements.

    Or, give the local building department and find out what
    *their* reccomendation would be.

    Sheesh! Dave, you're not re-inventing the wheel here.

    BOB

    Quoted message said:

    Practice safe eating - always use condiments

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.