Say I have a 60W device. I know running for one hour it uses 60 W x 3600 s = 216 kJ of energy. Does that mean it uses 216 kWh of energy? Or does kWh means 60 W x 1 hour = 60 kWh? I am confused because the units in 60 kWh is not in their simplified terms. More specifically, this pertains to a project that I am working on. From experimental values, I found that with X kg/s of water flowing through the heat exchanger and some temperature increase, I can find the power of the heat exchanger in kW. I would like to provide the values in BTU since that is just what people still use in the States. I realized BTU is an energy unit, not power, and 1 kWh = 3412 BTU. So I need to convert kW to kWh.