I have checked with my insurance company. They don't care if I put a commercial, non-residential range in my kitchen. I'd notify them in writing before proceeding, of course. Weight should not be an issue. 36-inch to 48-inch ranges weigh from 600 to 800 pounds, which is about five people. The basement is unfinished, so if I measure any deflection I can sister the joists or even add a post. I've talked to a local restaurant supply store. They are happy to sell me a used range. For a new range, they want to sell to a business, which I can do. They will only deliver to my front door, will not install, and the range will have no warranty - all perfectly understandable. The applicable building code has no provision for commercial appliances in residential dwellings. Then again, I've never pulled a building permit just to buy a new kitchen appliance. Interestingly, the code says nothing meaningful about makeup air or required CFMs in residential kitchens - I will look again, though. Visually - hmm. I did a quick sketch - maybe I can make this look palatable, maybe not. So, this brings me to the original issue, which is function and safety. I have friends with commercial ranges in their home kitchens. These ranges don't set the kitchen ablaze, nor do they turn the kitchen into a sauna, nor do they brand you like a calf if you brush up against them. They are not ''on'' at full-bore 12 hours/day, jammed in a room with more ranges, broilers, griddles, ovens, fryers, all working non-stop. I believe that, if properly installed with appropriate clearance to combustibles and appropriate venting and professionally installed gas connections, a commercial range is just as safe as any range. When I add the fire suppression and gas shut-off, I think it'll be safer. But I do need to get the venting right. This house is leaky, but hopefully as we work on it, it'll get tighter, and I don't want any backdrafting. The way I see it, the exhaust and makeup issues I'm wondering about are not unique to commercial ranges. Someone planning a 60-inch "professional" range with char-broiler would face the same issues. I know that discussions about commercial appliances on GW tend to elicit cautionary responses, which I understand and appreciate. But, for the purposes of planning HVAC, let's forget the "commercial" aspect. Let's pretend I'm planning a 60-inch Bluestar and for some reason I like to cook with burners on high and the oven door ajar and the char-broiler blazing.

I'm a little stumped but thought that you might appreciate a response. My guess is that grease will collect on the fan blades no matter what. What model hood is it? Are there filters and if so how often do you change or wash them? How often do you use the fan? Do you do much frying and sauteeing? I wonder if it's possible that due to light use and minimal fatty cooking methods the collection cups just haven't been filling up. Have you checked the outside vent? Is it clear or blocked? Personally I would think that if it was blocked you would be seeing a lot more grease and that it would be dripping from the blades and hood and the cups would be full. You might get better answers to this in the appliance forum. There are some extremely knowledgeable people about ventilation in there who know more than I. Hope this at least gets things started for you.

Unfortunately the Laurelhurst fans are not designed to exhaust grease. They are great looking though. You MAY be able to use a Nutone or wall fan that is acceptable for cooking areas and use a Laurelhurst Grille, which is available separately. However, even the grilles are pricey.

My guess is that it is your interior humid air and/or cooking plume moisture that you are exhausting that condenses on the ducting and eventually returns to the kitchen. Definitely insulate the duct. Run the blower for a couple of minutes to warm the duct before cooking anything that generates water or grease vapor. In addition, there should be a damper just above your hood, and another at or close to the exit of the vent duct. The lower will keep moisture from the duct when the blower is off, and the upper will keep cold air from settling in the duct.