Ventilation Hood Specs for Gas Range


  #1  
Old 06-27-02, 02:29 PM
cboyce3
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Ventilation Hood Specs for Gas Range

We're changing the range in our kitchen and getting a "dual fuel" range to replace our old electric range. How much air should the range hood exhaust fan be capable of moving? The new range has a gas cook top but an electric oven. The range is a standard 30" wide model. We're looking at 3 models which move 160 cfm to 360 cfm of exhaust and range in cost from $35 to $200.
 
  #2  
Old 06-27-02, 08:19 PM
jeff1
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Hi,

Unless your clearance to combustables is too close...gas ranges do not need a vent hood. A hood is nice for sure!! Takes away cooking smells, cooking greases, you get an extra light...but they are not required for the range. If you really want the hood and are venting outside...go with the higher CFM...I'd rather have too much power than get it all done and not have enough suction power. JMO

jeff.
 
  #3  
Old 06-28-02, 07:26 PM
cboyce3
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More cfm in a Range Hood Is Not Necessarily Better

Thanks for your comment, Jeff. I have read that with gas ranges one should not invest in too big an exhaust fan as it wastes energy/increases gas usage. I also read a comment that one should upsize the exhaust power of a hood hood when switching from electric to a gas range for removing the combustion products...as a safety issue. We definitely want a hood for all the reasons you state but we want to size it right. Since we're getting a Kenmore range, we'll probably have to ask them to recommend a model to handle our situation with cabinets at about 27 inches above. As it stands right now, between your recommendation and my guess, we'll probably go with the 360 cfm model.
 
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Old 06-28-02, 10:06 PM
jeff1
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Hi,

**I have read that with gas ranges one should not invest in too big an exhaust fan as it wastes energy/increases gas usage. I also read a comment that one should upsize the exhaust power of a hood hood when switching from electric to a gas range for removing the combustion products...as a safety issue.**

Gas ranges are meant to vent into the room...no issues with or without a hood

Increases gas consumption...my opinion only...poppycock

All the work is done by the flame under the pot...removing any of the heat from above the pots isn't going to add any extra gas usage that you will notice.

You'll like the new 360CFM hood!!

jeff.
 
  #5  
Old 06-28-02, 11:01 PM
T
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How many cfms for range hood?

The Home Ventilation Institute recommends 15 air changes per hour in a kitchen. Multiply the floor area by 2 for an 8' ceiling.

Example: Kitchen is 20' x 20' with 8' ceiling, that's 800 cubic feet.
So, 15 x 800 = 12,000 cubic feet per hour. 12,000/n = 60 minutes
n = 200 cfms
Thus the required range hood would be one that can move 200 cubic feet per minute (cfm).

" A word of caution here - remember our homes are very air tight these days - where will all this replacement air come from that is being expelled outside - the only source of air is back down your chimney on your fireplace or from the exhaust on you furnace or hotwater tank - very dangerous pollution - so be very careful of over sizing the range hood - maybe you do not need 650 or 900 cfm - if you do, then you must provide a fresh supply of air to feed these monsters."

"Why bother with a range hood at all ? The incidence of asthma and respiratory problems, particularly in children, has jumped by 61% since 1982 - American Lung AssociationIndoor pollution (not limited to the cooking zone only), coupled with poor ventilation was a probable cause for this high increase in respiratory problems-Mayo ClinicWhy the jump since 1982 - what's the significance here - in recent years our homes have become very efficient and air tight, particularly in the snow belt - the result is a huge reduction in the fresh air circulat-ing through our homes - our homes have become air pollution hazards. Approximately 60 lbs of cooking fat and airborne particles get "dumped" into the fabric of your cur-tains, furnishings and carpets every year, if you do not have adequate range hood ventilation. I am sure you have smelt an egg being fried on the first floor of your home whilst you were sitting in the loft - two floors up - smells great, but that's air pollution and fat invading your home. Good ventilation can reduce the symptoms and the conditions which increase the likelihood of contract-ing respiratory ailments. I am sure you will agree - YOU SHOULD BOTHER WITH A RANGE HOOD."

Range Hood Facts and Decision Sheet. Retrieved 29 June 2002. http://216.239.51.100/search?q=cache...n&ie=UTF-8</a>
 

Last edited by twelvepole; 06-29-02 at 07:28 AM.
  #6  
Old 06-29-02, 05:10 AM
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Hello C.Boyce3 and Welcome to my Gas Appliances forum.

As you can already tell from all the information gathered both here in my forum and from other sources, selecting a range hood can become an unexpected complicated process....

However, I am glad to know that both Jeff & Twelvepole have supplied you with indepth and detailed information from which to make your selection. I thank them and hope you do also.

In my opinion, if there is any doubt as to the selection you should choose, I would suggest you consider a unit that has a multi-speed fan.

Doing so would then allow you the option to select the appropriate fan speed based upon the item being baked and the cleanliness of the oven.

Oh Yeah! Select one that fits the provided space too....

Once again.
Thanks Jeff and Twelvepole for providing excellent information on this topic and your assistance while I was unable to access the internet....

Regards,
Gas Appliances Forum Moderator
Tom_Bart........"Fast, Fair, Friendly & Highly Proficient"......
TCB4U2B2B.....Company Enterprises.
Energy Conservation Consulting Services & Gas Appliance Problem Diagnostics and Technician Services.
 
  #7  
Old 06-29-02, 05:56 AM
jeff1
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**" A word of caution here - remember our homes are very air tight these days - where will all this replacement air come from that is being expelled outside - the only source of air is back down your chimney on your fireplace or from the exhaust on you furnace or hotwater tank - very dangerous pollution - so be very careful of over sizing the range hood - maybe you do not need 650 or 900 cfm - if you do, then you must provide a fresh supply of air to feed these monsters."**

Negative pressure problems.

jeff.
 
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Old 07-11-02, 05:32 PM
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Re: How many cfms for range hood?

Originally posted by twelvepole
The Home Ventilation Institute recommends 15 air changes per hour in a kitchen. Multiply the floor area by 2 for an 8' ceiling.

Example: Kitchen is 20' x 20' with 8' ceiling, that's 800 cubic feet.
So, 15 x 800 = 12,000 cubic feet per hour. 12,000/n = 60 minutes
n = 200 cfms
Thus the required range hood would be one that can move 200 cubic feet per minute (cfm).

" A word of caution here - remember our homes are very air tight these days - where will all this replacement air come from that is being expelled outside - the only source of air is back down your chimney on your fireplace or from the exhaust on you furnace or hotwater tank - very dangerous pollution - so be very careful of over sizing the range hood - maybe you do not need 650 or 900 cfm - if you do, then you must provide a fresh supply of air to feed these monsters."

"Why bother with a range hood at all ? The incidence of asthma and respiratory problems, particularly in children, has jumped by 61% since 1982 - American Lung AssociationIndoor pollution (not limited to the cooking zone only), coupled with poor ventilation was a probable cause for this high increase in respiratory problems-Mayo ClinicWhy the jump since 1982 - what's the significance here - in recent years our homes have become very efficient and air tight, particularly in the snow belt - the result is a huge reduction in the fresh air circulat-ing through our homes - our homes have become air pollution hazards. Approximately 60 lbs of cooking fat and airborne particles get "dumped" into the fabric of your cur-tains, furnishings and carpets every year, if you do not have adequate range hood ventilation. I am sure you have smelt an egg being fried on the first floor of your home whilst you were sitting in the loft - two floors up - smells great, but that's air pollution and fat invading your home. Good ventilation can reduce the symptoms and the conditions which increase the likelihood of contract-ing respiratory ailments. I am sure you will agree - YOU SHOULD BOTHER WITH A RANGE HOOD."

Range Hood Facts and Decision Sheet. Retrieved 29 June 2002. http://216.239.51.100/search?q=cache...n&ie=UTF-8</a>
It's interesting that 90% of range hoods installed these days are recirculating and offer 0 CFM of exhaust !!!

And code accepts it in most states !!
 
 

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