Wow! A rare case where the aesthetics part of the performance-aesthetics-economy: pick-any-two limitation is not a factor in hood selection. But first, given a sealed household, I would strongly recommend obtaining a furnace kit to use outside air. This will avoid the possibility of the MUA system not working perfectly and the hood causing negative house pressure and hence backdrafting of the combustion appliance. I know that such devices exist for Beckett burners, and would guess that there are adapters for other burners. As the OP correctly notes, a 200 cfm ERV is not going to cope with a 1200 cfm vent hood. (Actually, what would happen with a sealed house is that at full power, the hood would pull the cfm the ERV would let through into the now minus a couple of inches w.c. house pressure.) So MUA is essential, and in the mid-Atlantic region would be pretty uncomfortable in winter if unheated. Depending on one's tolerance for heat and humidity, cooling in summer might be optional or not. We are starting to get into the realm where performance-economy, pick any two is applicable. MUA can be roughly characterized as passive or active. By passive is meant no fan in the circuit. Active uses a booster fan to keep the house pressure stable. No-fan only works for simple ducting with a vent hood air flow controlled damper. (A recent post here provided some sources for these.) If a filter is used at 1200 cfm (or whatever flow actually could be pulled with all the doors and windows open, then the house pressure will drop. One can see on websites selling filter packs that the pressure drop at such flow rates is too large for combustion appliance safety, which require negative pressures not be greater than 0.03 to 0.06 inches depending on appliance type. Active is needed to overcome the filter restriction. It may be needed to overcome heating heat exchanger restriction and/or air conditioning heat exchanger (expander) restriction. The difficulty with active is balancing the MUA air flow rate against the variable hood flow rate such that the house pressure is near zero. This usually requires a control system of some sort, and can be a "project." What to do? What to do? Only one free-of-processing-controllers active MUA has occurred to me. In the simplest embodiment, the hood control is connected to two parallel wired identical fans, one in the hood exhaust path and one in the MUA path. Then the two will (try to) operate at nearly the same flow rate at every control setting, and one only needs to adjust the MUA duct restriction until it matches that of the hood path. More exactly, adjust the MUA path so that house pressure falls very little as the hood is turned on. Note that this doesn't account for bathroom fans, fireplaces, or other exhaust flows not due to the hood. In such cases, PID control of the MUA fan would be needed. In my case, due to a 1500 cfm hood, 1000 cfm over-oven vent, fireplace, and three bathroom fan household, I am building an active MUA that will use an axial blower in the 2000 cfm regime. It has to overcome the pressure loss of its intake vent, its filter, and its heat exchanger (which is hot water pumped from my oil burner). Control is via a Fuji PID controller operating from a BAPF differential pressure sensor. The motor power control is not yet selected, and a lot of sheet metal action is still needed, along with further attic revisions that I seem to have trouble getting to at the needed rate. I recommend the OP and/or his HVAC person read the "Kitchen Ventilation Systems Application & Design Guide" that may be found at Greenheck's web site. It periodically moves around, URL-wise, so a Google search by name may be fastest. Greenheck or one of its competitors may be able to provide what you need for considerably less agony than a do-it-yourself HVAC project would. kas

We used a Tornado II by Zephyr. It's an insert that we built a hood around to fit my situation. I saved quite a bit of money by buying my insert directly from an ebay dealer that I bought almost all of my appliances from. (saving-u-money) is his eBay handle. I can provide more info if you want to compare prices. Here's a photo of my hood. Though not completed, you can see how a liner works. You can also download a PDF info from Zephyr that will give you a drawing, schematic, and other info that will show you exactly what you will need to do this. I love my hood. The photo online shows that they've redesigned it a bit. Mine actually looks like the Tornado III, but I know it was a II with 1,000 CFM. FWIW, I love my hood. It's a powerhouse and doesn't blow you out of the water. It's a solid whooshing sound, not whiney and tinney. My brother lives next door about 300' away. (We both have 1.5 acres.) He has called me before to ask, "When's dinner?" because he can smell what I'm cooking. My kitchen vent is away from his house, too. When I've told him that I'm not grilling and I'm cooking inside and not outside, he can't believe it. It has to be this powerful hood. Here is a link that might be useful: Tornado II

May I make a suggestion? In Photobucket, make a new album, transfer all the kid/personal pictures into it, and lock it. The children are darling by the way, but you don't necessarily want to give them so much exposure. Leave all the architectural stuff in the original folder so that when we click on it, it will still be there vs a "broken link." You may want to make several new albums and sub albums for the rest of your photos and lock or not lock depending on what's in them. For instance, we took a trip to Europe this summer, so I made an album called "Europe 2013." Then I made sub albums for each of the 5 cities we went to, and each of those cities got some sub-sub-albums depending on what we were looking at. Back to the kitchen. This isn't a large kitchen, and that isn't a bad thing. A well designed smaller kitchen can be even more useful than a monster requiring roller skates to get from the fridge to the stove. I think with the larger appliances you might find that they crowd the space and leave you short on prep space. I so know what you mean about the Kohler Stages 45 sink! I tried to make that work in my small kitchen and it just wasn't gonna happen. I don't love where the DW is in this plan. If you think about unloading it, where are you planning to put your plates and glasses? You could put them in the uppers above the DW, but it's more awkward than other choices. I love having the plates in a lower drawer: Do you have the option of not doing a corner sink? If the sink moved under the right hand window and the DW just to the right of the sink, then you free up all kinds of prep space on the current space where the DW is while maintaining a landing spot next to the fridge. I like the idea of the corner sink and the view, but functionally, I think it takes up too much room in a kitchen that needs to be very space efficient. Is there a hood planned for that cooktop? I agree that if you could move it to a wall instead of on the peninsula, it would be better, and you'll love a clear peninsula where you can prep, the kids can color, and family projects can happen. I wouldn't trade the fridge and the ovens though. Functionally, I think the fridge works better where it is vs walking across open floor. You'll need to cross the floor to use the ovens, but they get used way less often than the fridge.

The duct need not be straight up, it can deviate in the attic so that the external cap or blower is in a good position. Pressure losses in short additional lengths of ducting and modest bends are small relative to the hood baffle pressure loss or imperfect make-up air pressure loss. The roofers will have to mess with the cap or blower if already in place, but I would ask them which they prefer as they have to guarantee the roof's zero leakage. Typical installation directions from such as Broan/Best/NuTone describe cutting into an already shingled roof. Part of the interface will have to go under shingles, and part will lie over shingles. Your contractor should also have an opinion. But I wouldn't hastily do ducting without having a complete hood system plan and a make-up air system plan.