What is the difference between a kilowatt (demand) and a kilowatt-hour (usage)?

Kilowatt (kW) is the initial amount of power pull, or demand, that is required to operate the lights, appliances, electronics, HVAC systems, machinery or whatever is being used that works with electricity. Currently, the homeowners do not pay any demand charges however, industrial and commercial buildings pay a very hefty price. SCE and SDG&E clients’ demand charges double in summer months, which significantly increase their electricity bills.

Kilowatt-hour (kWh) is the amount of power used over a period of one hour. All the clients get charged for this usage and solar panels are a great way to eliminate charges that occur due to kWh usage.