I have my home computer set to go into "sleep mode" when idle for a short time, and I assumed that by doing so I was saving lots of energy and that it was good for the computer by shutting down nearly every component while the computer is sleeping.
However, this website claims that using sleep mode "can result in more harm that good. Your memory is still fully functioning, which can lead to overheating and damage, so it's always better to fully power down and let your machine rest." and additionally, it states that it "costs about $50 more per year on your electric bill".
The website is sponsored by Bank of America and Visa, so I'd hope that they did their research, but it doesn't seem accurate, and is contrary to measurements of my own computer, which uses 1 - 2 watts in "sleep mode" (my Kill-a-Watt meter bounces between 1 and 2 Watts when measuring sleep mode power, and none of the components inside are warm to the touch).
At 1.5W, the computer should only cost around $2/year to keep it in sleep mode all day every day (at 15 cents/KWh for electricity), and 1.5W of power dissipation should not cause any heat problems at all, even with no fans running. To get up to the $50/year quoted on that website, the computer would have to dissipate nearly 40W of power while in "sleep mode."
The website dates back from Oct, 2012, but my computer is older than that, so I don't think that the information on the website is simply out of date.
Is it common for computers to use significant power in "sleep mode"? Doing so would seem to negate the entire advantage of having a sleep mode in the first place.
Granted, turning it off (or hibernating it) may be more sustainable, but I'm trying to strike a balance between usability and sustainability.