In my case the cook-top is on a peninsula, part of which is a bar configuration, and I wanted to move the cooking away from the bar as well as shifting the island hood away from the bar. However, I use a large island hood (also covers an induction wok hob) and it is about 34 inches above the cooktop surface. So with a high flow rate blower I can pretty much keep all cooktop effluent out of the house. The difficult to solve problem is capturing oven effluent when an oven door is opened. I have registers above the wall ovens connected to a separate ventilation system that try to capture, but there is just too much spillage into the room upon door opening to be immediately successful. The "eyebrow" scheme used in commercial cooking would be expected to be more effective, but far from fully effective. Any scheme built in by the manufacturer might dry out moisture in the oven unless a means of replacement were included. You might consider ways in which your alcove could be enhanced to curl the effluent that passes the downdraft around where it might have a second chance for capture. Sheet metal formed to resemble a closed off recirculating hood might help. Anyway, good luck. kas

There are many rules of thumb for cfm, even linear dimensions of the hood edges excluding walls. One can also calculate on the basis of effluent velocity and hood aperture. (I've covered that somewhere.) But all of these will, as pointed out above, likely end up being well over 300 cfm for any hood that would work with a 48 inch cooktop. Most of us would agree that if financially feasible, a properly heated, pressurized, balanced MUA system is needed, and, (in my view) the affordability of a 48-inch Wolf range should include the MUA cost in the project. However, there may be ways of circumventing some of the costs. One way (won't work for fireplaces) is to have any other combustion appliances (furnaces and hot water heaters and gas dryers) in a room that is isolated from the kitchen (air flow wise) with its own not necessarily well heated minimal MUA (after all, the flow rate for these appliances will be small). Then the safety issue is accounted for, even if the inspector won't care. Then a passive MUA design (a damper in a duct) passing outside air to a heater would be sufficient to pull in sufficient replacement air. The kitchen pressure would be low (lower if filtering is used), the hood flow would not be what one might expect, but the code would be met and safety achieved. A 10-inch duct with pressure sensitive damper flowing air (due to negative house pressure) past a heater of some type (think 100 kBTU/hr order of magnitude) would be the type of heater required, maybe larger in MN. You would save the cost of the big blower needed for pressure balanced MUA, and the cost of a proper pressure control system and its tuning. kas

My kitchen is fairly contemporary. I wanted an efficient hood so bought an undercabinet Broan that was new with features I thought would keep it from being noisy. Didn't buy the cheapest because wanted quality. Turns out there is a slant to the underside which I hate. I posted on this forum and some indicated that the slant would make the hood more efficient. Had I chosen to have a hood with a cover, I could have made the underedges of the cover totally horizontal and could have more easily covered up the slant. Details are a bit too complicated to post here but bottom line, I think the cover gives you some advantages later to get the exact look you want, that's my experience anyway. You can always get a stainless cover if you like stainless. I'm a newbie and not a pro at this so don't take my input as the last word. Good luck to you. Wish I would have put in the hood vent first before anything else. It was my biggest installation challenge. (I'm my own G.C.)

no foam mike_home, contractor is proposing blown insulation either fg or cellulose, only OP knows. just google baffles for attic ventilation OP. lots of pics there.baffles are installed on roof at eaves to do two things. one is to keep insulation at low point of eaves/soffits from clogging up air flow. the other is to establish a pathway for air to enter attic at soffit/eaves. attic ventilation that works is one of these three methods. all are stand alone, not strategies to be mixed. gable end vents. soffit/eaves may or may not have vents cut into them. soffit/eaves vents with ridge vent at peak of roof. or lastly soffit/eaves vents with passive vents installed on roof. the idea is to take air from soffits & vent from gable end, ridge vent or passive vents. google attic ventilation for more detailed info. prior to adding insulation minimal air sealing of air barrier (ceiling of living space) from living space to attic is done. for example recessed lights (Insulation contact not IC air tight recessed lights) would be addressed prior to insulation. much harder to dig out each area to be air sealed with newly installed insulation. fortunately, you can do a lot of air sealing from inside the living space. making as tight of an air barrier between living & attic spaces is one of the first steps to efficiency (and better air quality that goes along with it). it is easier to heat/cool a house with minimal air leakage. first area to air seal is house to attic. then floor to crawlspace (now that we have that info) once the air sealing is completed...then insulate. (3" closed cell foam installed on underside of floor, installed from under the house) if you have 8, 12 or 20+ inches of insulation & there is air moving through it...then it isn't performing. keep in mind that there is a diminishing return for more inches of insulation. the first 6" of insulation does most of the thermal barrier work, added insulation above this 6" saves you less & less $$ in utility costs. meeting code minimums is the least you can do. here in La. R0-30 is code, but people often have R-38. not a big jump in price, and not a big savings in utility costs. you make your own call on what to be installed. are you willing to do any work? (ie caulking etc) whats your location? best of luck