i think it will. electric products hates hot.

Thanks for the advice.

There's another really long-winded answer on here (mine).
The short version is: <b>If you can mount the TV over the fireplace where it doesn't get hot, then go for it.</b>
The distance away from the fireplace opening, whether or not here is a mantel shelf between the fireplace and the TV, and what type of fireplace it is (vented vs. unvented, etc.) all make a difference.
At least half of the fireplaces we install have TVs over the top. That being said, it's not usually the best place to put a TV because it may be too high for comfortable viewing.

Thanks for taking the time to explain!

short answer: yes the heat will damage your tv as it rises and gets into the tv vents.

solution: i installed a fan/blower which will push the heat into the room so I did not need an unsightly mantle. my fireplace is a direct vented gas. if you do not have the option of installing a fan/blower into the fireplace then I suggest you enter install a full mantle (which will encase the entire fireplace) or simply install a fire-safe suspended shelf between the fireplace and tv. This will re-direct the heat away from the TV and still keep a sleek clean look.

I have a NO vent fireplace with my cable box, dvd player, & tuner above with the tv in a nook. There is a mantle which you would think would direct the heat waves away, but it doesn't. There is also a small switched fan on the side of the FP...it still gets too hot and shuts the cable box down because it gets above 140 degrees. If I didn't have a reclining chair the tv would be too high for comfortable viewing. This is not an ideal configuration IMHO.