How would one know if 'what it will do' will be what one needs? 'What is needed' should be calculated  there are CSA, ASHRAE, and NFPA standards and guidelines for commercial and/or residential kitchen ventilation. Also without knowing the project details, skills and talents on the site; it behooves industry to warn anyone doing large scale residential kitchen exhaust - pulling this quantity of air out of ones house without providing for replacement air can lead to moisture problems (think mold) and most certainly carbon based gas poisoning IF heating with a natural draft furnace or boiler or have a wood burning fireplace or other naturally vented combustion appliance in the homeÂor have an attached garage or ÂorÂor Whatever Âis needed - be it 200 cfm to 1200 cfm of exhaust  has to be replaced with outdoor air and this Âmake up air becomes a heating, cooling and dehumidification load. Depending where in Canada this could be significantÂperhaps as high as 50,000 Btu/hr (or more) for heating and maybe even one to two tons of coolingÂit will all depend on the exhaust/mua calculation and the climateÂone canÂt be guessing on this stuff. In addition, if the outdoor air in the neighborhood is poor like in some areas of Ontario, or the make up air is pulled in from a bad location  like in the vicinity of the neighbors furnace exhaust - then there may also be additional IAQ issue to deal with. If the exhaust air stream feeds into the neighborÂs outdoor air intake  that can also cause problems for the neighbor  think your odors in their home. My recommendation if you are not a HVAC professional or not working with a professional and intend on doing this yourself  Stop, you may be putting your health and the health of others at risk - Contact The Heating, Refrigeration, Air Conditioning Institute of Canada for a list of certified designers in your area. Sorry for the black cloud - but please - for no cost  you can do a web search on occupant deaths related to ventilation and combustion in housing or contact - again for free - Canada Mortgage and Housing Corporation...Installing a 1200 cfm (+/- 1000 cfm) exhaust fan - is not a DIY project for the non professionals.

I don’t think you’ll get much feedback from people who have put a cooktop in front of a window because I don’t think it would occur to many people to do this. It seems like a bad idea. You will constantly be cleaning it. Bump a pot the wrong way and you can scratch or crack the glass. It seems what you are envisioning is a direct-set window, with the glass flush with the countertop/cabinets. This would mean if you ever had to replace the glass, you’d have to do it from outside by removing the trim, as the window frame would be behind the countertop and cabinets. What direction does the window face?

Than you for all of these great points and suggestions! After taping off the space, I think a bay of casement windows is out of the running. Three windows would be too little view and two casements would have the seam right in the line of sight. You bring up a great point to be careful with muntin layout because one could potentially be right in the center as well. I am currently leaning toward a 3-panel horizontal slider with 14-28-14 size panels or one large awning window. My fear with the horizontal slider is that is doesn’t seal in the winter as much as the awning and could be drafty. My fear with the awning window is that since it doesn’t open completely, it won’t let in much air in the summer. Prices for each are about the same. We won’t have trim but rather a dry wall return. My husband says in obsessing (I mean, maybe a little ;)) but I really want this to be a feature piece!

Is the new framing along the exterior walls built in front of an existing, finished exterior wall? Will those open exterior wall stud bays be insulated?  I would think the 10" flex duct could transition into square duct above the closet ceiling, then run inside the stud bays, then transition back to flex beneath the floor. Idk which way the floor joists run but it seems doable either direction.  This looks like it was just run whichever way was easiest for the installer and in the absence of a plan. It happens, can certainly be tightened up