Heat vs Kelvin Rating

[Horace]

I am curious if any of you science gurus out there could tell me if the heat generated from a 250w 10k bulb is more/equal/less than the heat generated from a 250w 20k bulb. I have my guesses to this question but I want to know from somone who knows this for sure. So please, do not just give me your theories, I can do that myself .

The reason for this question was a friend of mine noticed a difference between bulbs....

[aninjaatemyshoe]

The direct heat given off by the bulbs would depend upon the efficiency of the bulbs (lumens/Watt). 10K MH bulbs tend to be much more efficient than 20K bulbs. So, 10K bulbs should give off less direct heat than 20K bulbs. However, all of the energy emitted will become heat in the end. If they both use the same amount of energy, they will both generate the same amount of heat.

[Horace]

Originally posted by aninjaatemyshoe
The direct heat given off by the bulbs would depend upon the efficiency of the bulbs (lumens/Watt). 10K MH bulbs tend to be much more efficient than 20K bulbs. So, 10K bulbs should give off less direct heat than 20K bulbs. However, all of the energy emitted will become heat in the end. If they both use the same amount of energy, they will both generate the same amount of heat.

This is exactly what I figured. 250w is 250w. The energy is either emitted in Lumens or in Heat. So a bulb that emits more lumens, should emit less heat. Essentially that 250w of energy has to be split up evenly.

My friend said he noticed the 10k bulb heated his tank up much faster than a 20k bulb. He also said he noted the room got hotter with the 10k. In my opinion (based on what I know about the conservation of energy) this is not possible. Atleast for BOTH the room and the tank to be hotter.