Wow, a lot of confusion here....I'll take a stab at it if I may.
1000W of 56% efficienct leds will give off 440W of heat "straight away". The 560W of energy converted into light will mostly end up as heat in the end, too.
1000W of 28% efficient MH will give off 720W of heat, and the 280W of light will be eventually converted to mostly heat, too
BUT, having 2 times more usuable light will result in more being absorbed by the plants, and more space covered with the leds (at equal ppfd)
More light/w means more space/W = lower temperatures.
I guess in an empty room, both would end up producing 100% heat from their Watts ... but with plants, yes, you will have lower temperatures with more efficient lamps.
NO, 1000W with 1% efficiency will not give you the same temperature as a 60% efficient 1000W as long as plants are capturing some of that light ..
i fix that for you
generally a 1000 watts of leds will produce less Temperature in the grow room than a 1000watt hid.
Heat ≠ Temperature
Learn about it.