I wonder how many sleep/wake cycles would it take a day to outweigh the TCO decrease of the power bill with the TCO increase of the increased stress/amortization of the hardware, especially HDDs.
Probably a lot. My anecdata: I have had four Seagate HDDs in my desktop PC since 2007 and despite a couple of remapped sectors, they're still working fine.
I often power it on and off 1-2 times a day, and the drives are set to spin down when not in use. The SMART data for these drives shows approximately 37,000 power on hours and 17,000 start/stop cycles. That's about 4 years 3 months of actual power on time, and about 3 power cycles per year over the past 16 years.
Assuming 15 cents per kwh, that comes to $494 saved by shutting the drives down over the past 16 years. And I paid $232 total for the drives back in 2007.
Obviously YMMV, just thought it would be fun to calculate :)
That might possibly be close where you live, but not where I live. I need to heat my home at least 8 months a year and I heat using electricity (which isn't the smartest thing to do, but that's the way the house was built 30 years ago). It is too hot inside less than 4 weeks a year. So saving energy is done by trying to live in cooler rooms, but not by searching for small consumers.
I'm curious if you mean the 15 cents per kwh estimate is too high or too low? It's a conservative average for me in upstate NY over the past ~15 years.
If you're using electric resistance heat, then I suppose a running computer is kind of like processing power plus "free" heat :)
Prices obviosly differ a whole lot depending on the country. My point was not absolute monetary savings, but energy saving.
My school physics tells me that nearly everything you do with electricity at home will heat your home. Doesn't matter whether it's the baking oven, the computer or the fridge. So if you heat using electricity and live in cold climate saving energy for computers or household appliances just moves the same consumption to heating.
The big exception is heating water. That energy is typically lost to the sewer.
As long as you pay the same electricity price for your computer as for your heating, it does not make a differencd whether that's 7 or 50 cent or the 15 you estimated.
Oops. Yes, an average of 3 cycles per day, not per year!
I have the spin down timeout set to 20 minutes. But this is a desktop PC with intermittent usage (and different usage patterns over the years). They used to be in a RAID1+0 but now they're JBOD and I use them as scratch drives for random stuff.
