If you are a casual computer user (or a Linux power user), you can get rid of your huge, several-hundred watt desktop, and instead use a version of Linux, on one of these slower, but yet much more efficient computers.

GNU/Linux, such as Ubuntu can be tuned to your needs, and will run on much less power-hungry hardware than can Windows (especially Vista), or MacOS. And for people that are more techno-phobic, there are beginner-targeting computers with Linux preinstalled, such as the Eee or Dell’s Inspiron Mini.

Many of these devices fulfill the average user’s needs, while using less than 20 watts of power.

Thank you for starting this site, if everyone optimized their energy use (and other aspects of their daily lives), we could see significant progress toward solutions to the economic and environmental problems that face our world.

You can calculate the energy usage with the following:

Output (in BTU) / SEER rating = Energy used (in watts)

In the original example, our 30,000BTU (2.5 ton) unit would have had a SEER value of just over 8, which is very low. Most modern units have a value of at least 13 (required by most building codes since 2006). We’ve updated the chart to reflect a modern unit.

The point of the graph is to compare the energy consumed by the AC for 1 hour vs. other devices in the home. Even with a modern unit, it is clear what an energy hog the AC can be when running.

(And the source of the data was cited in the original chart as well)

A modern 2.5 ton (30,000 BTU/h) AC unit with even minimum efficiency (13 SEER) is 2307 Watts, not 3500. And, depending on the size of your home, probably won’t run 24 hours, especially not if you have a rhetorical home small enough that a window AC unit can cool it effectively (and that 4 CFLs will light it).

Also, this is an exact copy of a graph from this page (which has the same errors): http://michaelbluejay.com/electricity/cooling.html