That’s surprising. Usually battery life increases after rooting. It
sounds like an app isn’t allowing the phone to go to sleep. Try using
the app system tools to log activity. It will tell you which apps are
the most active and should help you see which one is preventing your
phone from sleeping.

Also, you can see what the phone reports when you go to Settings > About
Phone > Battery. It should display what’s using the most battery.

Here’s some good info on maximizing you battery life:
http://www.howtogeek.com/howto/25319/complete-guide-to-maximizing-your-android-phones-battery-life/