A watt-hour (Wh) is a unit of energy; it's a way to measure the amount of work performed or generated. Household appliances and other electrical devices perform "work" and that requires energy in the form of electricity. The joule (symbol J) is the SI unit of energy-a measure of the capacity to do work or generate heat. Newton-Meter (N-m) is a unit of energy. One joule equals the work done (or energy expended) by a force of one newton (N) acting over a distance of one meter (m). SI unit for force is Newton (N). 1N=1‌kg.m∕s2 Thus, kg.m∕s2 is the unit of Force not energy.