I have one over a fireplace, and I love it. the rest of that wall is windows, so it was the only spot. My fireplace is gas, and there are clear guidlines about the clearence from combustibles and the like. There are heat concerns. It's commonly stated that you can't have the TV on when the temp there is 95 degrees. Easy for me to monitor, I just keep the fireplace remote there, sometimes programed to turn off the fire when the area hits that. If the fireplace is woodburning, controling the heat could be a problem and you might simply have to turn the tv off sometimes. I suspect that the 95 is a purely random number, though. Lots of homes get that hot, and we haven't heard many reports in the media about flat screens failing from it. To me, watching the fire or watching the tv are different activities that I rarely want to do at the same time. I love having the fire on for conversation, reading, playing a game, and those are times I'd rather have the TV off anyway. We do burn the fire to take the chill off the room on movie nights, but at a pretty low level. As to veiwing angle: it's about 5 ft above the floor, and the seating is about 12 feet back. It seems a little odd if you are used to a conventional set just inches off the floor, but you quickly adapt. It isn't at all uncomfortable for me or any of my family [so far as anyone has ever mentioned], and the kids and dogs don't block the screen everytime they walk by. Overall, I think its a good solution for many rooms. Just be sure to plan for power and signal up there: you don't want a lot of visible wires.

If the furnace is right there, why don't you put in a hot air duct? That would be cheaper, easier, and more efficient.

calidesign- thank you for the drapery suggestion. Yes there is plenty of room onthe outside of the window and slider. The slider actually opens to that side- was thinking that might be awkward with the dogs coming in and out that door, but if we extend them far enough like you suggested then it should work. when you say the proportions are off for the fireplace — is there a size you’d recommend? Or is concept of doing a fireplace wrong?

Another consideration is convenient seating directed toward tv viewing..close enough ..and with tv mounted low enough to view without having to lay “back” and lookup...to view...sometimes a challenge in a big...tall room...never mind when there are multiple windows allowing a lot of sun shining in your eyes for daytime viewing