
The average desktop/monitor combination consumes up to 2000 kilowatt-hours (kWh)of electricity per year, of which 500 to 1000 kWh can be cut with simple power management.
According to a recent report the UK wastes £123m per year powering PCs out of hours. Each PC costs around £37 a year to run, but if you simply turn them off over night and at the weekend they cost just a £10 a year to run.
A desktop PC left on for 24 hours per day will create around 2,161lb of CO2 in a year.