Unlike old televisions that had cathode rays and varied from 65 to 133 watts depending on their size, new televisions and monitors produce relatively less heat. The word relatively is used because the bigger the screen, the more this heat will be.
For 50-inch screens, LED TVs can consume 100 watts. But plasma TVs found at thrift stores may use up to 300 watts.
The air in the enclosures is ventilated to remove the heat generated by the electronics. Therefore, placing the TV in the vicinity of excess heat can affect the performance of the TV. The example of the thermal range of some major TV manufacturers shows the lowest and highest temperature in which the TV can be placed:
Samsung LCD TV: 10 to 40 degrees Celsius
Sony LCD TV: 6.5 to 40 degrees Celsius
LG 4K LED TV: 6.5 to 40 °C