Earlier I posted how much I love my 50 inch Panny plasma from late 2007. Fantastic television with no problems out of it EVER and a fantastic image. BUT, it heats up a room!
IF I could get a plasma in 70 inches for around the same price and if it did not heat up the room, I'd buy it. But you can't and it does.
Take a look at the power consumption. It's been awhile since I compared the specs, but I remember the stuff from 2007 were horrifyingly power-hungry (read as "make a lot of heat"). In fact, that heat business stayed strong through 2010 I think. By contrast, the 65" 2012 Pana VT50 I think had an "average" power draw of 150 watts. Not much to heat a room any more.