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.
AOL Mail users (sorry, Mom) are on average spending $182 more per year on electricity than Gmail users (a difference of 18%).
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:
- Even more so than Yahoo Mail users, AOL households are likely to live in the suburbs, where homes are bigger (our data indicates 7% bigger relative to Yahoo homes) and families are larger.
- Across the rooms of their large residences, AOL households are more likely to own multiple Digital Video Recorders — energy-intensive devices that some studies have found to consume more electricity annually then a new flat panel TV.
- AOL users are more likely to use a desktop computer (which consumes 50-80% more electricity than a laptop), and so perhaps use other less energy-efficient appliances as well.
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.