Question: how many kwh does a light bulb use?
Answer: For example: A 100 watt light bulb uses 0.1 kilowatts each hour. It would take 10 hours for the light to consume 1 kWh of energy. If your energy company charges you a rate of $0.10 for each kWh, you would pay $0.10 to use a light every 10 hours.