Question: how much does a window air conditioner add to electric bill?
Answer: Power Cost For example, a 900-watt air conditioner running for eight hours would consume 7.2 kWh (900 watts * 8 hours, divided by 1000). If you pay 22.8 cents per kWh, running such an air conditioner will add about $1.64 per night to your power bill, plus taxes and fees.