Heat output
Wednesday, April 28, 2010
12:54 PM
Heat output
Heat output = energy expended.
In other words, a 28-watt laptop generates the same heat (over a larger volume) as a 28-watt lightbulb!
Heat output is measured in BTUs (British Thermal Units). 
1 BTU ≈ 1060 Joules = the amount of energy needed to raise one pound of water by one degree Farenheit.
1 watt = 3.41214 BTU/hour. 
One person generates  about 400 BTU/hour = 117 watts.