With MacBook Air launch in October 2010, Apple stopped adding Flash as default to Mac OS X. User can still download, install and run Flash, but they have to get it from Adobe’s website. When questioned about this omission Apple simply said they want users to have the latest Flash update and it’s easier to get it directly from Adobe. However, Ars Technica found out in their MacBook Air review that Apple might have more reasons to keep Flash out. In their battery life testing Ars Technica found out:

Having Flash installed can cut battery runtime considerably—as much as 33 percent in our testing. With a handful of websites loaded in Safari, Flash-based ads kept the CPU running far more than seemed necessary, and the best time I recorded with Flash installed was just 4 hours. After deleting Flash, however, the MacBook Air ran for 6:02—with the exact same set of websites reloaded in Safari, and with static ads replacing the CPU-sucking Flash versions.

This conclusion from Ars Technica was reported by various blogs and forced Adobe’s CTO Kevin Lynch to criticize the findings. He explained to Fast Company “It’s a false argument to make of the power usage. When you’re displaying content, any technology will use more power to display, versus not display content. If you used HTML5, for example, to display advertisements, that would use as much or more processing power than what Flash uses.”

This gave us an idea why not compare power usage for running Flash and HTML5 on a MacBook Air. As displaying Flash or HTML5 ads continuously for testing can be a problem we decided to run the test using video. We used the same Apple MacBook Air October event video, which is available in Flash on YouTube and in HTML5 (H.264 streaming) on Apple’s website to run the battery life tests.

We used a 13-inch MacBook Air with 1.86GHz processor for all the tests and the methodology we used for the tests was very simple. First we used the default MacBook Air setup that doesn’t include Flash to test battery life using H.264 streaming from Apple website. We ran the video with full brightness, at full volume, and in full screen mode. Once the video was finished we reloaded the website and again played the video till the battery died. After running the test three times for H.264 streaming, we installed Flash on the computer and again started the same test using YouTube this time for Flash video. As you would have guessed after every test we recharged the battery to 100% and restarted the computer.

In all the three runs H.264 offered better battery life performance when compared to Flash. In first H.264 streaming test the battery lasted 191 minutes, in second test 205 minutes and in the third test 195 minutes. While using Flash on YouTube the battery lasted 151 minutes in first test, 145 minutes in second test and only 140 minutes in last test.

We ran the same test three times so that possibility of error would be reduced and the average of three tests would give a conclusive result. On average, H.264 offered 197 minutes (3 hours and 17 minutes) of battery life and the Flash offered 145 minutes (2 hours and 25 minutes) of battery life on a 13-inch MacBook Air. Overall, H.264 video playback offered 26% more battery life than Flash video playback.

One thing we should note is that Apple’s website continuously streams the video with minimum buffering and YouTube can buffer the complete video in less than 10 minutes. This makes the result more impressive as in theory streaming should require more battery power for continuous processing of the video.

So in the end when it comes to battery life Flash is still a problem. Adobe should focus on improving Flash performance rather than claiming other technologies will also have same effect on battery life.