There are also less obvious reasons for adequate air flow at the hood than just pulling in air. One is that for baffles to work correctly in removing grease particles from the larger part of the particle spectrum, the air must be accelerated around the baffles, thereby achieving centrifugal impingement. 600 cfm for such a large area hood seems to me to be marginal for grease collection. Fan sizes vs. baffle hood sizes listed in the back of the Wolf Design Guide may provide guidance. A second is that the upwelling effluent has momentum, and when it hits parts of the hood it will tend to reflect away. It is desirable that the air velocity at the hood aperture be comparable with the effluent velocity of approximately 3 ft/s. (Comparable means not worse than one half, as then the reflected momentum will tend to become transverse flow that will be captured at the next baffle.) A 600 cfm at zero static pressure fan pulls 10 cubic feet per second, but in a duct/hood/baffle configuration, even with perfect MUA, will probably only pull around 7, depending on the particular fan curve and all the losses. With no MUA but a closed leaky house, maybe the actual amount is 5 cubic feet per second. Now a 4 ft x 2 ft aperture is 8 square feet, so the velocity averaged over the aperture is 5/8 feet per second. (Actual aperture vs. exterior hood size will vary, and there are various internal shape factors that can influence the effective aperture.) 5/8 fps is on the low side for cooking that generates significant grease and smoke. Other considerations such as cost and aesthetics compete with effectiveness, so compromises must be made. kas

I love our 48" Viking. There is plenty of room when dh and I are cooking at the same time and the extra space also comes in handy when I'm cooking alone. I love having unused burners to slide hot pots onto for cooling off or as landing space for hot items from the oven. It contains all the hot items to one space instead having them scattered across the counter on trivets. And there are times when all of our burners are used at once (we have 6 + a griddle.) I use the small oven most of the time for our family of 4. The large oven is handy when I cook mulitiple items at the same temp or when I use large cookie sheets. Having 2 ovens comes in handy for different oven temps and for when one oven is tied up by something baking for an hour that shouldn't be disturbed. Take your favorite baking dishes to the showroom to make sure they fit into the small oven. The dishes I brought were a 9" Pyrex pie pan and a 9x13 pan. They fit fine in our Viking but didn't in some other brands. The brand I was leaning toward got eliminated because the oven rack brackets decreased the usable space so much that I couldn't fit either of the 2 dishes I brought. Just reading the oven specs wouldn't have been good enough since it seemed the oven was plenty big. Dh was happy we ended up with his top choice by default. I would definitely buy another 48" range if I had to do over again. Getting a range with 2 ovens and plenty of burner/elbow space was a splurge that made a lot of sense to us.

dueceluxe I'm not sure if you ever got an answer to your question, but I'm going to chime in because in 2008 I was in the same boat. We have a 48" BlueStar in a 12' island, with a prep sink located about 48" away, which is where I spend my prep time. Frankly I wish people would focus on answering the direct questions, vs. lecturing about what percentage of prep/cook/cleanup time people "should" be spending in their kitchens, or in which direction they should be facing when doing so. The OP stated they were looking for an island hood for their cooktop, not IF they should be putting the cooktop in the island. For us personally, my prepping and cooking is very intertwined, and we entertain a lot. Ergo, I want to be facing my guests while prepping AND cooking, and not facing my guests during cleanup (THAT sink is behind the prep area against a wall), so the cooktop in the island is what we did and we (and guests) LOVE it and wouldn't go back. It's not for everyone, but it's definitely right for me. Having said all that, yeah, sadly the hood is going to be expensive. We went with a Best by Broan IEX222 51" with a 1500 CFM externally mounted blower. The pros are that the thing will suck up ANYTHING at full speed. The con is that we've had it for 7 years, and unfortunately have gone through 4 control modules or transformers on the thing (everything on it stops working). So nn my frustration I'm now researching replacement hoods, which is going to be $$. It's the price you pay for the style you want. Currently evaluating Cavaliere and Imperial 54" hoods....

My understanding is that the silencer has to go before the motor (i.e. vent liner --> silencer --> motor). It's silencing the fan and motor noise, so it wouldn't make sense to have it after the motor. If you have enough space in the attic to put an inline blower after the silencer, then you wouldn't need an external blower. For us, the silencer barely fits between the attic floor and ceiling, so we had to have an external blower. The contractor was worried it would be loud outside (it's on the slope above our deck) but it's fine.