> every watt of energy Watt is a measure of power not energy. Did you mean Watt-hour? The specific heat of water is about 4.2 kJ/kg/K. One joule is one watt

> every watt of energy Watt is a measure of power not energy. Did you mean Watt-hour? The specific heat of water is about 4.2 kJ/kg/K. One joule is one watt for one second, that is 1 J = 1 W.s. So one W for one hour (3600 seconds) is 3.6 kJ and is enough to raise the temperature of a kg of water by about 0.9 K You need to brush up on dimensional analysis :-)