Working in energy conservation, I frequently get the question “how long before I should turn my computer off?” People are wondering when it becomes most effective to turn your computer off for periods of time. Should you turn it off if you plan to be away for 15 minutes? 45 minutes? 3 hours? 24 hours? I’m here to give you the scoop.
However, before I go into the conservation part, let’s take a look at the technical one first. There are 2 parts to the majority of computers - the monitor and the tower. It’s much easier to turn the monitor on and off than it is to turn the actual computer. And knowing how much energy each one uses is important to answering this question. When thinking about turning your computer on and off, we need to assume that your computer and monitor are on a power strip. If not, the monitor and computer can draw ‘phantom load’ which means that the device is using energy, even when it’s not on. When your devices are plugged into the power strip and you turn the strip off, that means the computer and monitor are completely turned off.
According to the Department of Energy, the general rule of thumb is…
Turn off the monitor if you aren't going to use your PC for more than 20 minutes, but turn off both the CPU and monitor if you're not going to use your PC for more than 2 hours.
Also, the DOE mentions that most computers have a sleep mode.
Many PCs available today come with a power-down or sleep mode feature for the CPU and monitor. ENERGY STAR® computers power down to a sleep mode that consume 15 Watts or less power, which is around 70% less electricity than a computer without power management features. ENERGY STAR® monitors have the capability to power down into two successive "sleep" modes. In the first, the monitor energy consumption is less than or equal to 15 Watts, and in the second, power consumption reduces to 8 Watts, which is less than 10% of its operating power consumption.
It is important to note that the DOE does not consider screen savers to be energy savers. In fact, many screen savers can use more energy than not using one.
3 hours ago