I have a hydronic system (PEX in gypcrete, mostly raised foundation but some slab) in my 7,100 square foot home (actually, more square footage than that, since we did the garage, too). I can't speak to the issues associated with doing just one room but here are some things that I've learned along the way, some the hard way. 1. You can heat the house with a standard hot water heater (ours was a 100 gallon commercial model that also provided domestic hot water for half the house). But expect it to last only half as long (~ five years) because of the load that the radiant system puts on it. We replaced ours at great expense ($12K) with an 80 gallon Phoenix boiler/hot water heater: 96% efficient (vs. ~70% for a water heater), compact and should have a 20 year lifespan. 2. Use caution selecting the pad under any carpeting. Surprisingly, the carpet isn't a big issue for radiant floors but the pad can significantly impair the heat transfer. Best option: slab foam rubber (expensive and hard to find). Next best: corrugated foam rubber. Absolute worst: rebond. 3. Don't set the temperature back at night if you have a high thermal mass (e.g., gypcrete) system. It's actually less energy-efficient to bring the floor back up to temperature each morning than to maintain it throughout the night. It's OK to turn the thermostat down while on vacation. 4. Use the forum for the Radiant Panel Association (http://radnet.groupee.net/groupee/forums) to get opinions from installers on all sorts of radiant floor issues. 5. Finally, here are some pros/cons that not everyone considers with radiant systems. a) It takes a LONG time for the system to heat a cold house (10-12 hours or more). Having a forced air furnace as back-up is important if you turn the system down while on vacation. Likewise, if it's too warm in the house, it will take a long time to cool down after lowering the thermostat. b) Radiant systems heat your extremities better than other heating systems because the warmest part of the room is at floor level. This makes you FEEL warmer in a cooler room. c) Radiant systems keep the heat from rising to the ceiling in rooms with high ceilings because the heat is evenly distributed and can't readily be displaced by cold air in order to rise. d) If you have stone floors as we do, you'll love walking on them barefoot in the winter. We love our warm floors and won't trade them for forced air until we head for the rest home. Hope this helps. Bob

We have 3", 4" & 5" random width White Oak solid hardwood over our radiant floor heat. We're not on a slab though, so I'm not sure about that part of it.

Wianno - it's honed black Brazilian slate. John and David - thanks for the advice. I talked to the contractor last night and he said he thinks that if we reinstall one of our radiators, we might be better to go with electric and just use it as needed, rather than having an always-on hydronic system.. I will ask about this at the site John suggested, but any thoughts about this? Right now with the demo we have been down to one radiator, and even with a week of below zero temps last week, the kitchen stayed very comfortable.

@sarah hossain I'm not an expert like @kaseki is on vent hoods, but here's my best try at answering your questions: Is makeup air (MUA) absolutely necessary if your house isn't tight? Well, my house was built in 1985 before more modern insulation methods were used and isn't tight at all, but I still get better exhaust through bathroom fans when I open a window, and those are only 150 CFM. When you get into 300 CFM or higher for a vent hood, you'll probably want to open a window or door to help with airflow if you don't have MUA regardless of how leaky your house is. Lack of MUA whether ducted or via something like opening a window will actually restrict the effectiveness of your blower at any speed. I don't have MUA and am about to install a ducted hood like you want to do. I chose a Wolf hood for the premium under-hood capture space with tilted baffles and a 300 CFM blower. In my city, I am required to keep the CFM of my blower 400 or less unless I have makeup air. This is very common because it complies with the International Residential Code (IRC) and helps prevent dangerous gasses from being pulled from the water heater, fireplace or other appliances into your breathing space when a high-CFM blower is being operated. If you live outside city limits, you won't necessarily need to abide by any code, but I wouldn't put anything more than a 600 CFM blower in a house without MUA for safety reasons. Most cities will require a permit for inspecting the new ducting work, and the inspector is usually going to also be checking that your new hood meets whatever code has been established. In northern climates where homes are built tighter, some cities have adopted a 300 CFM limit without MUA. Other cities have made exceptions to the IRC and allow up to 600 CFM without MUA. The requirements could be anywhere in between, but I've never seen mention of any city's code that exceeds 600 CFM for any reason without MUA. Keep in mind that while ideally you would want to open a window if you don't have MUA, that isn't always going to happen due to convenience or outdoor temperatures year-round. Does a large home and open floor plan reduce my need for a make-up air system? Having a large home such as yours as well as an open floor plan probably does help with exhaust issues if you don't have a MUA system. However, at some point if you are running your blower at the highest speed setting for a long period of time, you will need some way to provide make-up air even if it is through opening a window. A blower rated for 600 CFM won't provide that much actual exhaust if the interior airflow is restricted due to lack of make-up air. Limited options for ducting out of a centralized kitchen. It sounds as if you're bounded on all sides with that kitchen. Staircase to the right, bedroom upstairs, sun room on another side, all of this leads me to wonder if you've considered a totally different option which I'll try to explain. In Germany and some other European places where air efficiency is critical, it is actually more common to install a good recirculating vent hood with filters and then a heated air exchange system about 6 feet away from the hood that helps to exchange air with the outside. This helps to preserve the heating/cooling in your home since the air that is put back inside the house is pre-heated, and it actually does a pretty effective job of removing the things you want removed from the kitchen airspace. I found this early in my search on hoods and don't know if I can re-find the links where I read about it, but it might be a really good option in your case. You could keep the range where it is, install an island vent hood with a deep under-hood capture area and replaceable filters and washable baffles. Then install this other air-exchange system somewhere else, and you may have what you want. If I can locate the link to more info, I'll try to post again here later.