Question:

I worked in an office for years where everyone just turned off their monitor at night and left their computers on sleep. Now that I work at home, I do the same thing, but my husband insists that I would use less energy by shutting down. I also worry about wearing out my computer by shutting down and starting up more often. My question is: which is better to shutdown my computer at night or put it to sleep?

Answer from faircompanies:

This is a great question because there are so many myths around shutdown, sleep, hibernate, screensavers, etc, but before I address the myths I will give you a quick answer: the ideal state for your computer (i.e. least energy consumption) is shutdown and unplugged. This is because even when it’s shutdown a PC uses “flea power,” or about 2.3 watts; the easiest way to avoid it, and any other type of standby power so common on electrical devices, is to set up your computer on a power strip that you can just switch off at night.

If you aren’t going to unplug, the sleep option is about equal to shutting down: in “sleep” mode a PC uses about 3.1 watts and in “hibernate” mode (a more secure form of standby where your files are backed up) it uses roughly the same 2.3 watts as the plugged-in shutdown option.

When to shutdown

Obviously, you don’t need to turn your computer off every time you step away from it, but the US Department of Energy suggests these guidelines:

• turn off the monitor if you aren’t going to use your PC for more than 20 minutes
• turn off both the CPU and monitor if you’re not going to use your PC for more than 2 hours.

Power-down and sleep modes

Whether you shutdown that often or not, you can also help to reduce energy usage by enabling your energy-saving features on your computer and monitor. For those computers that come loaded with this option, which is the great majority these days, you still have to enable the “sleep” or “power-down” feature. 

The US Department of Energy has a program that will enable power management automatically.

What computer to buy

If you’re shopping for a new computer, make sure it has an energy-saving mode. Go here, for the Energy Star qualified computer locator. 

As a general rule of thumb, keep in mind that macs and laptops use less energy. 

Finally, the myths 

#1 Turning your computer off and back on uses more energy than leaving it running.
The Lawrence Berkeley Laboratory debunked this myth regarding not just computers, but lights and other appliances stating that “the small surge of power created when some devices are turned on is vastly smaller than the energy used by running the device when it is not needed.” 

#2 Turning on and off your computer will wear it out.
This is a myth based on old technology. According to the Rocky Mountain Institute, “modern computers are designed to handle 40,000 on-off cycles before failure, and you’re not likely to approach that number during the average computer’s five- to seven-year life span. In fact, IBM and Hewlett Packard encourage their own employees to turn off idle computers, and some studies indicate it would require on-off cycling every five minutes to harm a hard drive.” 

#3 Screen savers save power.
This myth was probably inspired by the name “screen saver”, and while at one time they helped preserve older style monochrome monitors, today they don’t save anything and often use more power. “… certain complex screen savers have been known to not allow a computer (hard drive, CPU, etc.) to sleep and also cause the computers to use as much as twice the energy.“