Question [Q] [i9505] Official Google Edition 4.4.2 by Jamal2367 ROM Battery Life Question

Hey guys!
I have a few questions about this ROM. I just exchanged my 4s for an S4 yesterday, so I'm a noob. Welcome for me, I guess.

I followed a few tutorials and successfully rooted the device. Installed ClockWorkMod and then installed a ROM called Official Google Edition 4.4.2 by Jamal2367. Been in love with that KitKat look ever since it came out.

I did this without previously checking the battery life, since the phone is used. I was wondering if someone is using this ROM and how is their battery holding up. I'm getting some pretty bad battery performance. I was in the shower for 20 minutes, screen locked and music playing on half volume. It drained 6% out of the phone. Is it the ROM or is it the battery?

Thank you in advance and sorry if re-post.