Gmail Users Beat Yahoo Mail Users In Energy Thrift

Question: If I jettisoned my decade-old Yahoo email address – sorry, family! – and stuck exclusively to my Gmail account, would my household energy use plummet?

Alas, reading closely into Opower’s report on the electricity consumption of YahooMail users vs. Gmail users, which showed Yahooians to be far more power profligate, the answer is, not surprisingly, “no.”

yahoo mail vs. gmail energy use

image via Opower

“We can establish off the bat that the ‘email-domain versus usage’ relationship is one of correlation, not causation,” Opower said.

Still, it’s fascinating stuff from the energy report and analytics company.

Opower said that for 2011 it had email addresses for 2.8 million household electricity customers in its dataset; 756,303 gave a Yahoo Mail address while 395,553 gave a Gmail address. That huge sample gave Opower 99 percent confidence that an energy usage comparison would yield statistically significant results.

Opower added up the results and found that YahooMail users consumed 939 kilowatt-hours (kWh) more power per year than the Gmail people – 9,282 kWh to 8,343 kWh. Or, put another way: “the aggregate difference in annual electricity use between 1 million Yahoo households and 1 million Gmail households is…equal to the entire annual electricity consumption of Barbados, a reasonably well-off country of 287,000 people.”

What explains this gap? It’s not because either set of households lives in a particular climate, or uses a particular type of power for home heating, Opower said. Home size has something to do with it – Yahoo user, more suburban and rural than Google users, “are approximately 10 percent more likely than Gmail households to live in single-family residences (as opposed to apartments and condos).”

Nevertheless: “(E)ven controlling for home size, we found that Yahoo households are still more energy-intensive than Gmail households. Based on square footage data that we have for single-family residences, we found that the typical Yahoo Mail household uses 12 percent more electricity per square foot of living space (6.84 kWh/sqft) than the typical Gmail household (6.09 kWh/sqft).”

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.