Symbols for 1000 (not one million) Btu (British thermal units) per hour, a unit traditionally used in the U.S. heating and air conditioning industry to state rates of heating or cooling. One MBH equals about 0.293 071 kilowatt
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}