Cut Costs by Turning Off or Sleeping Your Mac

Cut Costs by Turning Off or Sleeping Your Mac

My approach to energy conservation is fairly robust. My spouse and I drive vehicles with excellent fuel efficiency, maintain our home thermostat at a brisk 62°F during winter days, and opt out of using air conditioning. We’re diligent about turning off lights when not in use, and our household appliances are all Energy Star approved. However, I typically refrain from powering down my late 2012 27-inch iMac overnight or allowing it to enter sleep mode.

In anticipation of potentially installing solar panels, I recently evaluated our energy consumption and explored whether turning off my iMac when not in use would significantly reduce our energy bills.

Cut Costs by Turning Off or Sleeping Your Mac

Surprisingly, the savings were minimal, though for those aiming to minimize their environmental impact, powering down or utilizing sleep mode might offer some peace of mind.

Here’s a breakdown of my typical weekday: I use my iMac for about 8 hours, and for the remaining 16 hours, it remains in idle mode with the display off — not in sleep mode. I adjust the settings so the display turns off after 15 minutes of inactivity, but the computer itself never enters sleep mode. This setup accommodates overnight processes and remote access via Parallels Access from my iPad. Over the weekends, my usage drops to roughly 2 hours per day, with the iMac spending about 22 hours in idle mode.

Assessing the power consumption of Apple devices is straightforward.

By visiting Apple’s Environmental Responsibility Report page, you can review the energy profiles for all Apple hardware dating back to 2008. From the 2012 data, I discovered that my 27-inch iMac consumes 79.8 watts when active, 20.6 watts in idle mode, 1.03 watts in sleep mode, and 0.22 watts when turned off.

After some calculations, I found that my annual energy consumption for the iMac totals about 315.4 kWh, costing roughly $34.69 based on my local utility’s rate of $0.11 per kWh. If I were to shut down the iMac for 9 hours daily, it would use about 248.7 kWh annually, saving approximately $7.33. Alternatively, setting the iMac to sleep during non-use periods would reduce its annual consumption to about 185.1 kWh, saving around $14.33.

Although these savings are modest, they’re not insignificant.

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Ryan is a dedicated writer for TUAW, bringing insightful and engaging content to Apple enthusiasts around the world. With a deep understanding of Apple products like the iPhone, iPad, and MacBook, Ryan offers readers a unique perspective on the latest news, updates, and trends. His articles are known for their clarity and depth, making complex topics accessible to all. When he’s not writing, Ryan enjoys exploring new tech and staying ahead of the curve in the ever-evolving world of Apple.