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mpasquar

kitchenaid 600 cfm vent hood but 108k btu rating??

mpasquar
11 years ago

Can someone help me understand matching CFM w/ BTU requirements? Everything I read said that you should assume 1 CFM for every 100 BTUs. Kitchenaid is offering a 36" vent hood capable of 600 CFMs but yet rated for operation up to 108k BTUs. Here is the link:
http://www.kitchenaid.com/flash.cmd?/#/product/KXU8036YSS/

There are many 36" cooktops that capable of 90k BTUs. Here is one such example:
http://www.kitchenaid.com/flash.cmd?/#/product/KGCU467VSS/

Would this combination violate most local codes? Or is matching CFM and BTU more so a decision based on how you typically cook - say only using 2 or 3 burners at once - and so 600 CFM is more then enough?

Comments (2)

  • will2kz
    11 years ago

    Your local code may not require a hood at all. Code almost always has something to say about how big a hood can be in your house, but sizing it to the range may or may not be an issue.
    My inspector, shockingly, said I didn't have to have a hood above my 48 inch Capital with over 128,000 btus of output. I've found the simplest way is to call your local inspector. They are usually nicer to tax payers than to installers/contractors... Just start by being polite and saying you are trying to find the "right way to do a job."

  • jwvideo
    11 years ago

    Good advice from will2kz.

    A point of clarification: the 1 CFM per 100 btu-hrs is mostly a rule of thumb and not a code requirement. There are other such rules of thumb. One is 100 CFM per linear foot of cooktop. (This is often suggested for lower powered gas units and electric stoves and cooktops.) These rules are designed to help folks size the hood, but they are not the only considerations.

    As kaseki has often pointed out here, CFM is only a part of the story. Focusing on just CFM misses important aspects of hood design. You need to look at other things such as the capture area and whether you have a flat ventilator type hood or one with an actual canopy. Wider and deeper is better than shallow and flat. (Another rule of thumb is to have a hood that is 6 inches wider than your cooktop (3" on either side) in order to do a better job at capturing the vaopor & etc. coming from the pots close to the side.

    A canopy is (usually) noticeably more effective in capturing and corraling steam and smoke than a flat bottomed hood. So a taller canopy style hood may be preferrable to a shallower, flat bottomed one if you've got the space for it. Sometimes you don't.

    Of course, how much power/capacity you use at any given time will depend on what and how much and how you are cooking. One advantage to higher powered hoods is that the greater capacity may allow you to run them at lower settings which will be quiter. But, again, this is personal preference (and budget), not a code requirement.

    But, going to a larger hood may put you under code requirements because of make-up-air (MUA) provisions. Some localities have adopted MUA standards, but many have not. The best way to find out what is "required" is to do precisely what will2kz suggested and call the inspectors.

    If you want to search on make-up-air, the commonly used abbreviation "MUA" is good to include in a search string.