A 400-W computer (computer plus monitor) is turned on 8.0 hours per day. If electricity costs 10 cents per kWh, how much does it cost to run the computer annually?

Question

Quizplus · Accepted Answer

The computer uses 400 W of power for 8 hours each day, so it uses 400 W * 8 h = 3200 Wh of energy each day. In a year, it uses 3200 Wh/day * 365 days/year = 1,168,000 Wh of energy. At a cost of 10 cents per kWh, the cost to run the computer annually is 1,168,000 Wh * (1 kWh/1000 Wh) * (10 cents/kWh) = $116.80.

A 400-W Computer (Computer Plus Monitor) Is Turned on 8