We’ve all heard that turning off your PC saves energy and is the responsible way to live a sustainable, green life. But is it? All my life I’ve heard that you should turn off your computers and other devices when you’re not using them. All my life up until recently.
Some say you shouldn’t turn off your computer every day because it wastes more energy turning it back on and powering up. So what’s the real story?
The US Department of Energy website states, “Though there is a small surge in energy when a computer starts up, this small amount of energy is still less than the energy used when a computer is running for long periods of time.”
Those at Energy Star also still prefer that you turn your computer off at night, for maximum energy savings. “We are all about energy savings, and when you shut off your computer at night, you save the most energy,” says Craig Hershberg, program manager for office equipment and consumer electronics. “Every little bit helps. It all adds up.”
So, there it is. Turning off is still better than leaving on. So, what else do you need to know about how to conserve as much energy as you can while using your PC?
The EERE recommends powering down your monitor if you aren’t going to use your PC for more than 20 minutes and both the CPU and monitor if you’re not going to use your PC for more than 2 hours. And don’t worry about the “stress” of turning your PCs off and on each night. Most computers will be outdated long before they cease to work from too many power cycles. PCs also generate heat, so turning them off also reduces building cooling loads.
Another good point: not only do computers use energy, they produce heat. In small amounts this is probably negligible. But at the office or school’s computer lab with multiple computers running all day – and *gasp* weekends, too – a lot of heat is produced, thus driving up the need for energy to cool the building.
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.” -EERE
So the moral of the story is: It’s still more energy efficient to keep turning off your computer when you’re done using it. The energy used by starting up is less than the amount that your computer would use while on all night or while you’re at class all day. For people who really have trouble pressing that off button every night, sleep or hibernate mode is the next best thing. Just remember, even in hibernate mode, it’s still using energy.