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Discussion in 'iMac' started by galaksy, Jun 15, 2014.
I'm wondering if I bought it, how much electric bill I would pay more vs. using just my laptop.
There's plenty of information about that at the Apple web site:
A new 27-inch iMac would consume about 80 watts at idle, up to around 230 watts at maximum CPU load.
Asleep, the load would be considerably less, near the amount of current used when the iMac is completely off, and just plugged in.
Apple says less than 1 watt while sleeping.
Your laptop would only be consuming your power when the power adapter is plugged in. Max power draw would be whatever the power adapter can supply - for Macs, that would be up to 85 watts. Sleeping, according to Apple, would use slightly more power than a sleeping iMac! Still, only just more than 1 watt while sleeping. A sleeping retina MBPro uses a little less than 1 watt.
Again, for the laptop, you don't pay out for power unless the power adapter is plugged in. Without that, your only power usage is the battery drain.
That's not entirely accurate. You need to account for efficiency, the adapters are not 100% efficient (nothing is), so if it's supplying supplying 85 watts, it's consuming more than that.
Easiest thing to do is buy a kill-a-watt and see for yourself how much power any device is consuming.
Has any one measured how much watts and dollars worth of electricity were being consumed by the iMac and MBP per month?
It depends on how much long it's turned on, what you're doing, etc.; everyone's mileage will vary.
If I had to guess, it's probably like $10 difference and I run mine 24/7.
Perhaps they have in the iMac forum??
The ratings are actually what the adapters are consuming, not what they supply.
In that case, I stand corrected.
That isn't true. The 60w magsafe adapter for my old 13" MBP shows a maximum output of 16.5v and 3.65a. wattage = volts * amps, and in this case the output is 60w.
Since the conversion isn't 100% efficient, so that means that it can draw more than 60w.
No, I stand corrected:
You are correct, sorry for the misinformation
Generally devices have the power draw and sometimes the efficiency reported, but that's not the case with chargers/PSUs, where it's the output that is specified. This actually seems to be common for devices, that are designed for a wide range of input voltages, as the efficiency and the draw actually depend on the input voltage. I had never noticed this before, so thanks for pointing it out