Outlier

You’ve got mail: How AOL and Hotmail households consume electricity

  • By Barry Fischer
  • June 20, 2012

Many readers enjoyed our post last week about how/why Yahoo Mail subscribers spend $110 more per year on electricity than Gmailers. But, some commenters were curious about AOL and Hotmail. That got us curious too.

Our initial analysis of the relationship between email address and electricity consumption focused on Yahoo Mail and Gmail because they were the most popular domains (representing 1.15 million homes) in our data set. The next two most common email services were AOL and Hotmail. And so today we examine the energy use of an additional 594,000 homes, corresponding to AOL Mail and Hotmail.

The results…

AOL Mail users (sorry, Mom) are on average spending $182 more per year on electricity than Gmail users (a difference of 18%).

AOL Mail users use 18% more electricity than Gmailers

The electricity consumption of Hotmail households, meanwhile, falls between that of Yahoo users and Gmailers.

What are a few factors that could explain AOL Mail users’ outsize electricity use?

Thanks to some prior research from Hunch.com, we can propose a few contributing factors for AOL households’ high energy consumption:

And finally, some gentle advice for all email users

Whether you’re on a laptop or desktop, the next time you’re going to step away from your computer for more than 15 minutes or so, think about putting it in sleep mode (or even easier, set this to happen automatically by following these simple instructions). You’ll use a lot less electricity (>70% less) and save up to $75 a year.


Methodology: Annual electricity usage of households is based on 2011 data. The average consumption difference across users of the four email domains is statistically significant at the 99% confidence level based on a t-distribution. AOL/Gmail difference of $182 per year is based on the average 2011 US retail electricity rate of $0.118/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.

About Outlier

Outlier explores trends in how people are using energy in the US and around the world. Pulling from an unprecedented (and still growing) amount of energy data—currently drawn from 50 million homes—Opower crunches energy-use information from more than 90 utility partners every day, and cross-references that with weather, household, and demographic information to produce compelling analyses in the Outlier series.