Which Small Actions Make the Biggest Difference?

07/18/2008 05:12 am ET | Updated May 25, 2011

As the notion of "going green" has continued to grow, the number of lifestyle choices and changes we can all make has grown with it (or maybe even a little faster). "Unplug your cell phone charger," you hear, or "eat less meat," all in the name of saving the planet, saving the environment, or some other equally big-picture-type action. But which ones really make a difference?

A professor at the University of Cambridge, Dr. David MacKay, has put together "Sustainable Energy - Without the Hot Air" (pdf here), a rough draft of what will be a free book scheduled for both paper and electronic publication later this year. In it, he crunches a bunch of numbers and distills down various purportedly "green" actions, along with a handful of these many of us do almost every day, to see which ones really make a difference.

Photo credit: *Zara at flickr

His results are pretty dang interesting. For example, driving a car 30 miles per day ends up using 40 Kilowatt hours (kWh) each day; taking one long (8800 mile trip) airplane trip averages out to 33 kWh over an entire year, so you can either stop driving altogether for a year, or just skip the European vacation.

On a smaller scale, what about those cell phone chargers? Turns out, most modern chargers aren't pulling much from the grid when you aren't using them -- only about 0.01-0.05 kWh per day. Projected over a whole year, that's about as much energy as it takes to draw a bath -- 5 kWh. So, while you probably ought to unplug your charger when you aren't using it anyway, it'll save as much energy to just skip a bath.

Turns out, sometimes you're better off skipping the bath. Photo credit: riot jane at flickr

In an age when carbon emissions get the lion's share of the press as the global villain responsible for our warming globe and the rest of the peripheral problems that causes, it's refreshing to see each of these actions distilled down and expressed in something that's easy to relate. Light bulbs in an average home use 4 kWh each day, and heating and cooling an average home uses 38 kWh each day; which is likely to save you more with an efficiency upgrade?

Of course, MacKay's numbers aren't perfect -- the professor relies on lots of assumptions that aren't going to hold true for everyone -- and the numbers might not come out the same if replicated, since he's calculating in the U.K., where energy costs are higher than they are here in the States. Still, the numbers will remain (roughly) relative, since it takes the same amount of energy to heat water here or in Europe...where that energy comes from, its impact on the climate and environment, and its cost in dollars and cents, well, that's another story for another post. Still, the point is this: by expressing his work in something we can all relate to, MacKay's calculations give us all information we can use for good.

So what do we take away from this? I think we can all agree that we can each do something to make our world a better place, but what? Armed with this information, you don't have to guess which actions will have the most immediate, most positive impact.