Question: are box fans expensive to run?
Answer: For example, for a 100-watt fan, 0.1 times 12.79 is 1.279 cents per hour. Let's say you run this fan for twelve hours a day on average. Therefore, the cost for a month would be 1.279 into 12 into 30 days, which comes to 460.44 cents or around $4.6 a month.