Question: how much money does a 1000 watt light cost to run?
Answer: You need to divide your wattage by 1,000 (1,000 kilowats in 1 watt). So, if we were to run a 1000 watt grow light 18 hours a day with the kWh rate we gave earlier, our formula would be: 1 x $0.1559 x 18 x 30 = $84.186/month.