With an Ultralight class of machine that the Zenbook UX21 has to compete in, battery life is a very important watermark. After all, if you have to tether back to the wall with your thin slice of techno-coolness too often, what's the point of building such featherweight notebook? Below are our worst and best-case battery life test results, with Battery Eater Pro. Also, please note that, in the same benchmark chart, we have listed simple web browsing up-times as well.
 |
| Battery Life Test |
| Heavy and Light Workloads |
|
In terms of our standard BatteryEater Pro test, the UX21 offers respectable battery life, on the order of about 3 hours in this worst-case test condition, besting machines like Dell's XPS 15z and the ThinkPad Edge by Lenovo. However, as indicated by the top gold bar here in the graph, if you're just browsing the web and checking email, you can expect over 4 hours of available computing time.
