by Guest » Wed Mar 23, 2005 4:26 am
The BTU is based on temperature rise of a pound of water when heated. There are several types of BTU depending on the starting temperature of water.
I recommend the mean BTU = 1055.87 J or
the international BTU = 1055.056 J
Other published values (NIST SP811) range from 1054.68 to 1059.67
(there are some similar problems between the calorie and the Joule)