Led or lcd puts out less heat?

Most televisions described as LED televisions are currently still LCD based but simply use LED illumination instead of cold cathode tubes. The LED illumination is somewhat more efficient and therefore less energy is converted to heat by the back lighting system.

The latest generation of televisions are the true LED models, normally describned as organic LED or OLED. Unlike LCD televisions, these use LEDs to directly generate an image. The LEDs are therefore only turned on when they are needed. This substantially reduces the amount of energy being put into the illumination and so reduces the heat being generated.

A typical LCD television with cold cathode lighting runs at around 100W. A similar LED backlit LCD model will draw somewhat less while the new OLED models are expected to reduce power consumption significantly.