never put iMac to sleep

Joined
Nov 1, 2007
Messages
1,251
Reaction score
80
Points
48
Location
Swansea - South Wales
Your Mac's Specs
21 M1 Pro 14" MBP, 23 M2 Pro Mac Mini (MacOS 14), iPhone 15 Pro Max (iOS 17), iPad 6 (iPadOS 17)
Hi everyone

My 27" iMac is my main computer - it holds all my documents, music, films, photos, etc.

At present I am using my newly acquired macbook air much more but store everything I do on my iMac. I also use it for home sharing which entails having iTunes switched on. This entails asking someone to wake it for me but there's not always someone here.

So, my question is whether it's safe to leave my iMac in its never sleep mode or is this unwise?

Thanks, Nick
 
Joined
Jul 15, 2014
Messages
759
Reaction score
142
Points
43
Location
West Sussex, UK.
Your Mac's Specs
2021 iMac 24" M1 512/16/8/8 Sonoma. 2013 iMac 20.5" 3.1 i7 16GB Catalina. iPhone 13
I never use the sleep mode on either my PC or iMac and haven't had any problems. It certainly isn't a safety issue as far as I am, aware.

I suppose the purists would say that it isn't very green but what the ****!
 
M

MacInWin

Guest
Nick, what I would do (and have done here) is have the CPU never sleep, but let the display sleep. That way the system is constantly connected and available for home sharing, but the big power hog, the monitor, is not burning up your money.

I keep it that way because I use the iMac as a driver for my home automation and don't want not to have it available when I want to change something from my iPhone app. My iMac has been in that mode for close to four years.

I also have the iMac set reboot on power and to login automatically and the home automation software in the boot up sequence so that if for any reason the power fails, it will reboot when power returns and resume home automation control. On my iMac, running Mavericks, it's under System Preferences/Energy Saver, check the box "Start up automatically after a power failure."
 
C

chas_m

Guest
It's okay to have the Mac not sleep if that's what you require. It does use a bit more power (since the hard drive and CPU don't get to rest) but this is not a huge amount.

If you can identify specific things you need to have on both machines and just want to keep them in sync, you could look at something like Chronosync to do that.

Alternatively, you could have someone set the iMac to wake on network access. That would let it sleep when you're not using it, but wake up when you try to connect with it from the MBA.
 
M

MacInWin

Guest
On the power front, I just ran a quick test on my iMac. Power on, screen dark, it draws 45W, with screen on, it jumped to 105W. So with it on and screen dark, it's not terribly wasteful of electricity. At 45W, it's drawing 39.5 KWH per YEAR, so you can get what you are paying for electricity and calculate what it costs to run your iMac continuously. At my rates in Winchester, VA, where it averages US$0.10 per kWh, that works out to be US$3.95 for the year (current exchange rate makes that about £2.62 GBP per year). I don't know what your rates are, Nick, but from a quick search of UK electricity prices, it looks to be higher for you. I saw £0.13 per kWh in London, which at current exchange rates works out to be about US$0.19 compared to my US$0.10. So even if we assume it's double my rate, that still works out to be less than US$8/year for you, or £5.31. YMMV, of course.
 

pigoo3

Well-known member
Staff member
Admin
Joined
May 20, 2008
Messages
44,212
Reaction score
1,422
Points
113
Location
U.S.
Your Mac's Specs
2017 15" MBP, 16gig ram, 1TB SSD, OS 10.15
...that works out to be US$3.95 for the year …

Hopefully I didn't make a mistake. According to my math I get $39.50.:)

- Nick
 

pigoo3

Well-known member
Staff member
Admin
Joined
May 20, 2008
Messages
44,212
Reaction score
1,422
Points
113
Location
U.S.
Your Mac's Specs
2017 15" MBP, 16gig ram, 1TB SSD, OS 10.15
Nope, it's $3.95 (39.5 kWh * 0.10). Check your decimal point!

Here's my math:

- 45w/hour x 24 hours = 1080 watts/day
- 1080 w/day x 365 = 394200 watts/year
- 394200 watts/year divide by 1000 to convert to kw = 394.3kw/year
- 394.3hw/year x $0.10/kw = $39.42

$39.42 electrical cost/year.

- Nick
 
M

MacInWin

Guest
ARGGH! I dropped a decimal point in calculating the kWh. You are correct, it's 394.2 kWh/year and so then $39.41/year.
 
OP
nickyr
Joined
Nov 1, 2007
Messages
1,251
Reaction score
80
Points
48
Location
Swansea - South Wales
Your Mac's Specs
21 M1 Pro 14" MBP, 23 M2 Pro Mac Mini (MacOS 14), iPhone 15 Pro Max (iOS 17), iPad 6 (iPadOS 17)
Thanks everyone

I'll work out the cost to see if it's prohibitive and if so leave it at the max of 3 hours it's at now
 

pigoo3

Well-known member
Staff member
Admin
Joined
May 20, 2008
Messages
44,212
Reaction score
1,422
Points
113
Location
U.S.
Your Mac's Specs
2017 15" MBP, 16gig ram, 1TB SSD, OS 10.15
I dropped a decimal point in calculating the kWh.

No problems man. Either way…was just curious & wanted to know the exact answer.:)

- Nick
 
Joined
Jun 26, 2008
Messages
351
Reaction score
25
Points
28
Location
Mississippi
Your Mac's Specs
iMac and Macbook
I turn my iMac off every night for some reason. Sleep for my macbook and turn it off about twice a week.
 
Joined
Jan 20, 2012
Messages
5,067
Reaction score
429
Points
83
Location
North Carolina
Your Mac's Specs
Air M2 ('22) OS 14.3; M3 iMac ('23) OS 14.3; iPad Pro; iPhone 14
I turn my iMac off every night for some reason. Sleep for my macbook and turn it off about twice a week.

Hi Nancy........ - not sure if the above is just a statement or a possible question? Plus, 'off every night for some reason' is not clear?

If you are wondering about turning your computer off or leaving the machine on, the take a look at this recent related THREAD, which you may have already seen. Dave :)
 

Shop Amazon


Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Top