Unit of measurement of power. Very commonly recognised in electricity but applicable to the rate of generation, conversion, use or dissipation of any kind of energy. For example, Tour de France champion Bradley Wiggins is quoted as saying that his strategy is to keep up a steady 400 watt output; an airliner on landing approach would dissipate kinetic and potential energy at a combined rate of (say) 20,000,000 watts.
Wind speed
Factor potentially affecting energy consumption in buildings but not easy to take into account because of compound effect with air temperature. More..