Question: how much does it cost to have an electric fan on all night?
Answer: The equation is: Cost = power (kilowatt) × time (hour) × cost of 1 kWh (pence). The Sun also asked energy experts from Energyhelpline to estimate the cost of running a fan for 12 hours a night, and they found that it'd cost you from 7.76p to 15.59p on average.