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How much does it cost to charge an iPhone?

Guest Author

From the #OpowerOWN classic blogs library:

Many aspects of Apple's iPhone 6 line are indeed, as the company has stated, "bigger than bigger." From screen size to sales numbers, the new devices pack a hefty punch.

But at least one thing about the iPhone 6 and iPhone 6 Plus is spectacularly small: their energy consumption.

Following up on our iPhone 5 analysis a couple years ago, we returned to the Opower lab to measure how much electricity it takes to charge the latest Apple devices from 0% to 100% full. Then we modeled those results across a year to determine their annual energy impact and cost.


Charging the iPhone 6 costs $0.47 per year

We found that, like their predecessor, the iPhone 6 as well as the iPhone 6 Plus require a trivial amount of electricity:

Using a Watts Up Pro Electricity Consumption Meter, we discovered that giving a full charge to an iPhone 6 uses about 10.5 watt-hours of electricity. If you do that 365 days a year, you're talking about about 3.8 kilowatt-hours in total -- which, at an average US retail price of 12.29 cents per kilowatt-hour, comes out to just $0.47 per year.

The iPhone 6 Plus, thanks to its significantly larger battery, draws more electricity per fill-up (16.8 watt-hours) than its little sibling, but users are likely to charge it less frequently than the 6. Based on a charge frequency of once every 1.46 days. Plus owners paying US electricity prices can expect to shell out $0.52 per year to energize their device.

These cost numbers slightly outstrip the $0.41 required annually to power their iPhone 5. That makes sense given the iPhone 6 generation's across-the-board bump in battery size and screen dimensions.  

The iPhone 6 Plus may bend in your pocket, but it won't bend your energy bill higher

A household device using just 4 kilowatt-hours per year is negligible in the context of a home's yearly electricity consumption. In the US, charging an iPhone 6 represents 0.04% of the average home's electric bill.

By way of comparison, Opower has shown that giving personalized energy management advice to utility customers reliably reduces their electric usage by 1.5-2.5%, and oftentimes even more. In other words, it's pretty darn easy to offset the energy impact of your iPhone.

Based on this information, one could quickly come to the conclusion that the iPhone 6 will only increase your energy bill by a teeny-tiny bit. But that's not the full story. That's because using the iPhone 6 is actually quite likely to decrease your energy bill.

For reasons that we detailed in our 2012 blog post about smartphones, the iPhone 6 and similar pocket-sized devices may well lower your overall energy consumption for a couple reasons. 

First, people are increasingly using smartphones -- and especially phablets like the iPhone 6 Plus -- to do things that they have historically done on computers, televisions, and gaming consoles. Second, as shown below, the modern smartphone uses much less energy than those larger devices (e.g. PC’s and TV's) that they are displacing.

For more insight on how the iPhone 6 and other super-efficient smartphones are transforming the way people use energy, read our comprehensive iPhone 5 analysis from 2012. For more details on our iPhone 6 calculations.


Special thanks to Ben Ratcliff, Amir Raminfar, Tony Wang, and Nikki Serapio for assisting with device testing. Graphics by John B. Lee. Follow @OpowerOutlier on Twitter.

Methodology: Device power requirements were ascertained via a Watts Up Pro Electricity Consumption Meter, using an Apple 12W USB Power Adapter.

For the iPhone 6, we adopt a simplifying assumption that the typical user will charge their device once per day, starting in the off position, from 0% to 100%.

For the iPhone 6 Plus, we assume that the typical user will conduct a full charge (i.e. from 0% to 100%) once every 1.46 days. This assumption is based on Apple's internal device specifications, which suggest that on a single charge, the iPhone 6 Plus can go for an arithmetic average of 1.46 times longer than the iPhone 6 can in delivering a given function -- talk time (1.7x), standby time (1.5x), internet use (1.2x), video playback (1.3x), audio playback (1.6x).

The iPhone 6 consumed 10.5 watt-hours to charge, taking 1 hour and 48 minutes. Multiplying 0.0105 kWh/day by 365 days = 3.83 kWh per year. At the average US residential rate of $0.1229/kWh, annual charging cost is projected to be $0.47 per year.

The iPhone 6 Plus consumed 16.8 watt-hours to charge, taking 2 hours and 35 minutes. At a charging frequency of 250 times per year (once every 1.46 days, as explained above), we multiply 0.0168 kWh/charge by 250 charges per year to get 4.20 kWh per year. At the average US residential rate of $0.1229/kWh, annual charging cost is projected to be $0.52 per year.

Inputs for bubble chart comparison of annual electric use of devices are sourced from the June 2014 report from the Fraunhofer USA Center for Sustainable Energy, "Energy Consumption of Consumer Electronics in US Homes, 2013". Laptop - 55 kWh per year; Desktop - 186 kWh per year; Primary Household TV - 274 kWh per year. Xbox One usage (233 kWh per year) is sourced from a 2014 report from NRDC.

Nebraska equivalency: At a per-unit annual electric consumption of approximately 4 kWh, 10 million new iPhone 6 units will use about 40 million kWh per year. In 2013, Nebraska used 30,022 million kWh over the course of year, corresponding to a daily average of 82.25 million kWh, and a half-daily average of 41.13 million kWh.

Data Privacy: All data analyzed here are completely anonymous and treated in strict adherence to Opower’s Data Principles.

Author’s note: The analysis and commentary presented above solely reflect the views of the author(s) and do not reflect the views of Opower’s utility partners.


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