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Need feedback re Wolf hood sizes and 2 cfm motors

Posted by mdrei (My Page) on
Tue, Jun 25, 13 at 21:02

After reading these forums for weeks I've decided to purchase a Wolf 30', All Gas (R304) range and a 30' Wolf Pro vent hood (under cabinet). The hood installation will require removal of an existing over range MW (with recirculating fan) and the new duct work will run straight out the back as the hood will be mounted on an exterior wall.

I'm bounded on the hood width at 30" but have a choice between 10" tall, 22" deep, 500 cfm (internal blower)...or one 18" tall, 24" deep with either 600cfm or 900cfm internal blower. The 24" tall cabinet above the hood will be compromised with either selection but aesthetically I think the 10" tall hood will look better and leave me a usable, albeit, shorter cabinet space above the hood. However, I've read enough on these boards to have me leaning heavily toward the 18" tall hood because it offers the 24" depth and I'm willing to live with the slightly more 'boxy' look and 4-5" (basically unusable) space left over for the practical gain in surface area. Lastly, I should note that I'm 6'5" so I'm having the hood mounted at 36" above counter surface (max height).

So...can anyone present a strong argument to go with the 10" high hood? If 18" tall hood is the obvious practical choice, does the blower cfm choice (600 vs 900) make a big difference given the range underneath and kitchen setup? I believe these hoods are manufactured by Wolf these days (internal parts sourced elsewhere, I'm sure). With that, any thoughts on whether the often cited suggestion that a higher cfm blower will provide a more quiet operation (at similar lower output) and is that a enough of a reason to go with higher cfm?

Any/all feedback is much appreciated.


Follow-Up Postings:

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RE: Need feedback re Wolf hood sizes and 2 cfm motors

I'm in your shoes as far as looking for a hood for my 30" Wolf R304, and we are looking to buy in the next few days. Our R304 has been installed since February (it replaced an older JennAir downdraft), and we haven't had any ventilation at all since then other than opening a window. We are not big into frying or woking and only occasionally do stinky food. In reality there have only been a couple of times we have even felt we needed a hood. Plus, for the most part, we only have two burners going at a time on top. Heat from the oven exhausting is an issue, and since it got hot out we have been using our electric wall oven rather than the gas Wolf so as not to heat up the kitchen too much. We live in a cold climate, so the extra heat output from the range is nice in the colder months.

Our primary goal will be to have a hood to remove hot air expelled by the range in the summer heat. In the past four months there have only been max a half a dozen times when we needed to open the window specifically to deal with cooking fumes or output or smoke. And, the wall and cupboard area by the range are not showing any evidence of a lot of grease coating them.

So for all of these reasons, and because we have a ton of constraints as far as hood size, we plan to go with something smaller than either option you are discussing. On our short list of hoods the largest hood we are considering is probably smaller than the smaller one you discuss. Having lived with this range already for months we are comfortable with this decision. We know it will work for us. What is best for you and your cooking style may be another story.

I too have read everything here for ages now and have come to an understanding that what is recommended here as maximal is often for an unconstrained situation in a kitchen gut or in new construction where everything can be planned around the absolutely optimal hood that will take care of a range with all four burners and the oven blazing away at the same time.

Many of us who are doing minor remodelings or just appliance upgrades do not have the luxury of following all of that advice.

Good luck with your decision. Whether I gave you a compelling argument to go with the 10" I don't know.


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RE: Need feedback re Wolf hood sizes and 2 cfm motors

The first requirement is for the hood aperture to overlap the rising and expanding thermal plume containing the grease effluent. If you don't generate grease vapors, then the hood rules may be different.

The second requirement is for the flow rate maintain an adequate velocity at the hood aperture (and the baffles or mesh filter) to ensure that the captured plume is contained. This means that the local velocity at a point where air moves through the filter should equal the plume velocity (up to three feet per second). Because baffles and meshes partially fill the space they occupy, it seems that hoods work OK with perhaps half that velocity at the aperture, leading to a requirement for about 90 cfm per square foot. Note that the velocity is partly driven by total BTU, so the Finnish papers on this subject (referenced at my Clippings) should be consulted for particular cases.

The third requirement is to have a fan/blower that can move the required cfm at the pressure loss that the ducting, hood transitions, baffles, and restricted make-up air have.

The fourth requirement is to have a duct diameter that keeps the flow velocity up so grease not captured by the filter doesn't stick to the ducting, this is about 1000 ft/min.

The fifth requirement is adequate make-up air.

The sixth requirement is to not hit one's head on the hood, so it should be placed where that won't happen. Higher means a need for larger aperture for capture, so the cfm will have to rise. And one is back to the first requirement.

kas


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RE: Need feedback re Wolf hood sizes and 2 cfm motors

Kaseki...you are like the GW fluidics professor and your feedback is valuable. Thanks for the education.

Needinfo...thanks for your thoughts. You've given me more to think about. I've noticed the parallels in our status (and purchases) based on your previous posts. We also don't fry foods on a daily basis but venting all odors and grease is my objective with this hood. Kaseki's points are noteworthy given the boundaries of retrofitting an existing kitchen and the height at which I'll mount this hood. MUA isn't a factor, as far as I can tell, since I don't have any other gas appliances (someone correct me if I'm misguided on that assumption). Vent power will be important, at 36" off the surface of the range (and the constraints of the surface area), for the times when I do sear something or fry fish and switching to a back burner isn't desirable to me. I don't want to overspend but I don't want regrets 6 months down the road, either. I also know there are options at a fraction of the cost but functionality and quality are my priorities. Decisions, decisions...


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