Question: how much does it cost to run an air conditioner overnight?
Answer: It's common for a central air conditioning system to use 3,500 watts, so let's roll with that and the average national kWh cost – that's 13.2 cents – to get an idea of a rough average running cost. Let's also assume that you're running the unit for eight hours per day. This setup will cost you $3.70 per day to run.