Our house has some really great, wood-burning fireplaces. As the living area was setup when we bought it, literally the only wall-space available to mount a TV was over the fireplace. The previous homeowner, after I mentioned to my wife about finding a better place for the TV, assumed I was talking about the height of the mount and stated that the height wasn't too bad. He then started complaining about the quality of "the TVs they make nowadays", stating that he had replaced their living room TV - because it's the one they used the most - four times and only once was it under warranty. I didn't have the heart to tell him that his beloved, wood-burning fireplace and TV placement were killing his TVs.Yeah, it's not ideal placement, but I can only control so much. The mount I'll use does have a visible temperature sensor and the fireplace is gas, so I'll be able to shut off the heat quickly. So it could be worse.
After we bought the house, we remodeled the kitchen, created a new master suite, and replaced the open, stairway banister with a solid wall just to mount the entertainment equipment away from the fireplace. Of course, for me it was more than just the TV, since I have a five foot wide, floating entertainment center I built a few years ago that mounts a few feet underneath my TV mount.
Side note for anyone with wood-burning fireplaces or for anyone who smokes (even if you "don't smoke in the house")...
1. Spend the money and invest in at least MERV 13 or, preferably, MERV 14 air filters for your HVAC system.
2. Invest, if not a feature of your existing one, in a thermostat that lets you force 15-30 minutes of airflow per hour (meaning it runs just the blower for the required time if the unit wasn't already heating/cooling enough during the hour) to force complete circulation of household air multiple times per day.
3. Change the filters out regularly.
This will do several things for you. First, it'll make your HVAC run more efficiently by eliminating hot/cool spots and having more often but shorter overall heating/cooling times throughout the day. Second, it will likely make a huge difference in your family's allergies during the spring and fall. Finally, it will likely double the average lifespan of electronics in your house.