I've been having high CPU usage in AE when idle, nearly 100% of all 4 cores on a MacBook Pro, reducing battery life from 5-6 hours to under 1.5, spinning up the fans, and making the rest of the system less responsive. Found out the culprit is a process called CEPHtml Helper that is spawned by most Adobe CC apps (AE, PS, Illustrator, Permiere) when they launch. To stop it from happening, you need to remove the file called CEPHtmlEngine.
In Finder:
/Applications/Adobe After Effects CC 2015/Adobe After Effects CC 2015
(Right-click > Show Package Contents)
/Contents/MacOS/CEPHtmlEngine
I just archived it and deleted the original. This restored AE CPU usage when idle to a sane <1%. I haven't found a place where deleting the file negatively affects anything yet, although I assume it has some function (but whatever it is, being able to use CC on a laptop is more important). The process is mostly the same for the other Adobe apps, but sometimes the file is in a slightly different folder within the app's package.